Synthesis of alkylene-bridged diphenyl-oligoynes

FULL PAPER

DOI: 10.1002/ejoc.200500851

Synthesis of Alkylene-Bridged Diphenyl-Oligoynes

Christian Klinger,^[a]Otto Vostrowsky,^[a]and Andreas Hirsch*^[a]

Keywords: Alkynes / Macrocycles / Oligoynes

A general synthesis route for the preparation of oligoynes

stabilized by alkylene bridges is reported. The corresponding

macrocycles contain oligoynes with up to eight conjugated

triple bonds. The stabilization of the conjugated sp-oligoyne

rods was achieved by bulky terminal phenylic endcaps span-

ning the alkylene chain to isolate the individual acetylenic

rods and to avoid polymerization. Alkylene chains with up

to 40 methylene groups were employed. The two terminal

acetylene functions were introduced prior to the oligoyne

elongation by twofold introduction of additional C₂-acety-

lene or C₄-butadiyne building blocks. The final step was the

intramolecular acetylene coupling upon which very large

macrocycles with up to 62 ring members containing segre-

gated sp-, sp²- and sp³-segments were formed.

Germany, 2006)

represented anchor groups for sterically demanding

Frechét-type dendrimers and bulky silyl moieties. Diplati-

num-endcap-protected oligoynes from tetrayne to hexayne

rod lengths were recently prepared,^[8,11]and the opposite

terminal transition-metal endcaps additionally bridged with

two long and flexible alkane (polymethylene) chains. De-

pending on the bridge’s length, the flexible chains twisted

around the central carbon rod and could adopt double-

stranded helical conformations.^[8,11]

We report here on the first approach of stabilizing purely

organic endcapped oligoynes by long alkylene brigdes con-

sisting of up to 40 methylene groups linking the corre-

sponding phenyl termini. The basic idea for this synthesis

was the initial preparation of the two alkyne termini con-

nected by the alkylene linker followed by the subsequent

construction of the oligoyne chains starting from both ter-

mini by formation of the first two acetylene functions. After

the successive elongation of the oligoyne chains using vari-

ous acetylene coupling methods the synthesis of the stabi-

lized oligoynes is completed by an intramolecular alkyne

homocoupling reaction (Scheme 1).

Introduction

The investigation of very long oligoynes^[1–5]has recently

received increasing attention.^[6–12]Conjugated oligoynes

represent unique building blocks for the design and con-

struction of new molecular architectures such as molecular

wires.^[8,11]Furthermore, oligoynes have been investigated as

model systems for the hypothetical polymeric sp carbon al-

lotrope “carbyne” –(CϵC)_x–.^[7,8,13,14]The synthesis of car-

byne remains a great challenge. This is due to the fact that

the stability of oligoynes decreases considerably with in-

creasing sp-carbon-chain length. A major pathway for the

decomposition of long oligoynes is intermolecular cross-

linking and polymerization. The smaller the intermolecular

distance between the oligoynes is, the easier is the polymeri-

zation.^[15]As a consequence, strategies for the stabilization

of oligoynes have been developed by introducing building

blocks at the termini in order to prevent a close approach

of the individual alkyne chains. Examples are the use of

bulky end-groups, such as dendrimers,^[7]as well as the

wrapping of the sp-chains by alkylene bridges spanning the

organometallic termini.^[8,11]For example, the synthesis of

polyynes containing up to ten triple bonds, which span two

redox-active rhenium fragments as protective units, was de-

scribed by Gladysz and co-workers^[16]by applying classical

hetero- and homocoupling techniques. The same group also

reported the first structurally characterized hexayne con-

necting two platinum metal complex fragments.^[8,11,14]We

recently developed 3,5-dihydroxyphenyl endcaps as protect-

ing groups in the synthesis of α,ω-diphenylpolyynes with

up to ten conjugated triple bonds.^[7]The phenolic groups

[a] Institut für Organische Chemie, Friedrich-Alexander-Uni-

versität Erlangen-Nürnberg,

Scheme 1. Schematic representation of the preparation of oligoyne

macrocycles starting with the protecting diphenyl termini. i) For-

mation of the acetylenic termini, ii) alkyne elongation and iii)

macrocyclization.

Henkestrasse 42, 91054 Erlangen, Germany

Fax: +49-9131-8526864

E-mail: andreas.hirsch@chemie.uni-erlangen.de

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Synthesis of Alkylene-Bridged Diphenyl-Oligoynes

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gave the bis-terminal diynes α,ω-bis(4-tert-butyl-2-ethynyl-

phenyloxy)alkanes 10a–c (m = 12, 14, 16) in 95–85% yield

(Scheme 3). The yields decreased with increasing chain

length. Elongation of the two terminal alkyne functions of

10a–c by cross-coupling with an excess of TMS–acetylene

(11) under Hay^[20]homocoupling conditions led to the for-

mation of the TMS-protected terminal bis(diynes) 12a–c.

The excess of 11 prevented intramolecular self-coupling of

the starting materials 10; however, a large amount of the

dimer coupling product 1,4-bis(trimethylsilyl)-1,3-buta-

diyne (13) was formed, which had to be separated by col-

umn chromatography. From the subsequent deprotection of

12 with K₂CO₃in wet THF/CH₃OH the bis(diynes) α,ω-

bis(2-butadiynyl-4-tert-butylphenyloxy)alkanes 14a–c were

obtained. As 14a–c decomposed rapidly during isolation,

characterization was abandoned, and after a short aqueous

workup and drying, the compounds were immediately em-

ployed for macrocylization by homocoupling according to

Hay.^[20]The coupling reaction was performed in high di-

lution in order to suppress dimerization and polymeriza-

tion. With yields of Ͻ 10%, relative to the TMS derivatives

12a–c, the dibenzocycloalkanetetrayne macrocycles 15a–c

were obtained (Scheme 3). The tetraynes 15a–c appeared to

be stable and had been dried and kept in high vacuum for

hours without decomposition; in solution they remained

stable for several months.

Results and Discussion

The Synthesis of the Protecting Units

For the protection of 1,3,5,7-tetrayne rods, oligomethy-

lene bridges with 12, 14 and 16 methylene groups were se-

lected for the synthesis of the corresponding macrocycles.

Longer alkylene bridges with 20, 32 and 40 carbon atoms

were used for the protection of the long 1,3,5,7,9,11-hexa-

yne carbon rods in the hexayne macrocycles. The starting

compounds 1,12-dibromododecane (1a), 1,14-dibromo-

tetradecane (1b) and 1,16-dibromohexadecane (1c) (1a–c, m

= 12, 14, 16) were obtained by conventional reduction of

the corresponding dicarboxylic acids and subsequent bro-

mination with HBr. The required α,ω-dibromoalkanes 1d–f

with chain lengths of C₂₀, C₃₂and C₄₀were prepared ac-

cording to a method of Gladysz et al.:^[9]ω-Tetrahydropy-

ranyloxyalkyl bromides 2a–c were transformed into the cor-

responding Grignard reagents 3a–c (n = 6, 12, 14). Two

molecules each of the organomagnesium compound 3a,b

and 3c were linked with 1,8-diiodooctane (4) and 1,12-di-

bromododecane (1a) under Li₂CuCl₄catalysis, respectively,

and the bis-THP ethers 5a–c (m = 20, 32, 40) were obtained

(Scheme 2). Subsequent bromination with 2,4,4,6-tetra-

bromocyclohexadienone (6) according to the method of

Tanaka and Oritani^[17]led to the corresponding α,ω-dibro-

moalkanes 1d–f (m = 20, 32, 40). To assemble the stabilizing

bis(benzaldehyde) units 8a–f (m = 12, 14, 16, 20, 32, 40),

two molecules of 5-tert-butyl-2-hydroxybenzaldehyde (7)^[18]

were bridged with the α,ω-dibromoalkanes 1a–f in DMF/

K₂CO₃and isolated by precipitation at –30 °C (Scheme 2).

Scheme 3. Synthesis of the macrocyclic α,ω-diphenyltetraynes 15a–

c. i) PPh₃, CBr₄, CH₂Cl₂; ii) LDA, –80 °C; iii) excess of H–CϵC–

TMS (11), TMEDA, CuCl, O₂, acetone; iv) K₂CO₃, MeOH, THF;

v) TMEDA, CuCl, O₂, acetone, high dilution. Yields: 15a (7%),

15b (8%) and 15c (1.3%).

Scheme 2. Synthesis of the protecting oligomethylene-bridged di-

phenyl termini 8a–f. i) Mg, THF, heat; ii) I–(CH₂)₈–I (4), Li₂CuCl₄,

THF, –20 °C; iii) Br–(CH₂)₁₂–Br (1a), Li₂CuCl₄, THF, –20 °C; iv)

2,4,4,6-tetrabromocyclohexa-2,5-dienone (6), PPh₃, CH₂Cl₂; v) 5-

tert-butyl-2-hydroxybenzaldehyde (7), K₂CO₃, DMF, 80 °C.

All compounds as well as the intermediates of the syn-

thesis were fully characterized by H- and ¹³C NMR spec-

troscopy, IR and UV/Vis spectroscopy, mass spectrometry

1

Synthesis of Dioxacycloalkatetrayne Macrocycles 15a–c

The carbonyl olefination of the bis(aldehydes) 8a–c ac- and elemental analysis. The NMR spectra of the target tet-

cording to Corey and Fuchs^[19]yields the bis-1,1-dibromo- rayne macrocycles 15 revealed the expected C_2vsymmetry.

2-phenylethenes 9a–c, which upon elimination with LDA The NMR spectra of the C₁₄-bridged derivative 15b are

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1

Figure 1. a) H NMR spectrum (400 MHz, CDCl₃, 25 °C) and b) ¹³C NMR spectrum (100.5 MHz, CDCl₃, 25 °C) of the 28-membered

tetrayne macrocycle 15b (* = solvent).

shown as representative examples in Figure 1. The signal dehydes) 8d–f gave the bis(1,1-dibromoolefins) α,ω-bis[2-

for the two magnetically equivalent O–CH₂groups (H6) ap- (2,2-dibromoethenyl)-4-tert-butylphenyloxy]alkanes

9d–f

pear as one triplet at δ = 4 ppm. The assignment of the (Scheme 4). Upon elimination with LDA the terminally un-

signals of the phenyl H atoms was achieved by the analysis saturated α,ω-bis(4-tert-butyl-2-ethynylphenyloxy)alkanes

of their coupling multiplicities. The twelve methylene 10d–f were obtained. The subsequent sp-elongation with 1-

groups were observed as a group of partially resolved sig- TMS-1,3-butadiyne under homocoupling conditions gave

nals (H7, H8, H9), as well as the intensive peak of the hy- only very low yields, similar to the syntheses of 12

drogen atoms from the tert-butyl methyl groups, all between (Scheme 3). However, the cross-coupling of 10d–f with 1-

δ = 1–2 ppm (H4 in Figure 1, a). All the signals for the sp- bromo-4-(trimethylsilyl)buta-1,3-diyne (16) gave rise to the

alkyne C atoms in the ¹³C NMR spectra of the tetraynes formation of TMS-protected terminal bis(triynes) 17a–c in

15 are well resolved and appear between δ = 60 to 80 ppm reasonable yields (63%, 21% and 11%). The (trimethylsilyl)-

(Figure 1, b). Six signals were found for the aromatic C butadiyne 16 was obtained upon treatment of 1,4-bis(trimeth-

atoms (C1, C2, C3 and C4) and could be assigned ylsilyl)butadiyne (13) with MeLi/LiBr and AgNO₃/NBS

groupwise by means of a DEPT spectrum. The ¹³C signals in two steps.^[14]From subsequent deprotection of 17a–c

of the methylene bridge C atoms appear in the range be- with K₂CO₃/MeOH/THF the terminal bis(triynes) α,ω-

tween δ = 25–34 ppm, where also the signals of the tert- bis(2-butadiynyl-4-tert-butylphenyloxy)alkanes 18a–c were

butyl groups are located. The ether O–CH₂(C7) methylene obtained. Because of their labile nature, they were immedi-

groups appear as one singlet at δ = 69.3 ppm.

ately allowed to react without further characterization. Fi-

The UV/Vis spectra of the different tetrayne macrocycles nal macrocylization by homocoupling of 18a,b with

15a–c were almost identical, the wavelengths of the π-π*- TMEDA, CuCl, O₂in high dilution (3.8 m) in acetone

transitions found in the alkyne region between 350–450 nm according to Hay^[20]gave the 38-membered and the 50-

(see below).

membered dioxacycloalkanehexayne macrocycles 19a and

19b, respectively, with yields up to 33% (Scheme 4).

Attempts to elongate the bis(triyne) 18c with 1-bromo-4-

Synthesis of Dioxacycloalkanehexayne Macrocycles 19a–c

Similar to the syntheses of the tetraynes 15a–c (trimethylsilyl)butadiyne (16) to a bis(pentayne) by a Pd-

(Scheme 3), the carbonyl olefination of the bis(benzal- catalyzed coupling reaction similar to a Sonogashira coup-

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Synthesis of Alkylene-Bridged Diphenyl-Oligoynes

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Scheme 4. Synthesis of macrocyclic α,ω-diphenylhexaynes 19a–c and octayne 20. i) PPh₃, CBr₄, CH₂Cl₂; ii) LDA, –80 °C; iii) Br–CϵC–

CϵC–TMS (16), BuLi, THF, 0 °C; CuCl, pyridin; iv) K₂CO₃, MeOH, THF, v) TMEDA, CuCl, O₂, acetone; vi) [Pd(PPh₃)₂Cl₂], CuI,

NEt₃, CH₂Cl₂, 0 °C Br–CϵC–CϵC–TMS (16) (diluted, 3 mmol); vii) K₂CO₃, [Pd(PPh₃)₂Cl₂], CuI, NEt₃, CH₂Cl₂, 0 °C, Br–CϵC–CϵC–

TMS (16) (concentrated, 30 mmol). Yields: 19a (33%), 19b (18%), 19c (58%), and 20 (1.1%).

1

Figure 2. a) H NMR spectrum (400 MHz, CDCl₃, 25 °C) and b) ¹³C NMR (100.5 MHz, CDCl₃, 25 °C) spectrum of the 50-membered

hexayne macrocycle 19b.

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ling^[21]failed. Performing this reaction in high dilution

(3 m), we obtained the 58-membered macrocycle 19c in

58% yield as the intramolecular coupling product. By the

same transformation in tenfold higher concentration

(30 m) and with

a larger amount of Pd catalyst

(0.009 equiv.), the 62-membered dioxacycloalkaneoctayne

macrocycle 20 was obtained as the main coupling product

in 1% yield only, and characterized by mass spectrometry

and UV/Vis spectroscopy (Scheme 4). The hexayne macro-

cycles 19a–c were extraordinarily stable and were dried and

stored over days. All the three target compounds 19a–c as

well as the corresponding intermediates were completely

1

characterized by H and ¹³C NMR spectroscopy, IR and

UV/Vis spectroscopy, mass spectrometry and elemental

analysis. The NMR spectra of the ring-closed hexaynes

19a–c also reveal the expected C_2vsymmetry as do those of

the above-mentioned tetraynes 15a–c. As an example, the

NMR spectra of hexayne 19b are shown in Figure 2. The

¹³C NMR spectra (Figure 2, b) showed the expected six sig-

nals (C7–C12) between δ = 63 and 78 ppm, which are due

to the alkyne C atoms. The signal for the O–CH₂C atom

(C13) appears at δ = 69 ppm.

The UV/Vis spectra of the different hexaynes 19a–c are

almost identical to each other, irrespective of the oligometh-

ylene chain length. The comparison of the UV spectra of

the hexaynes with those of the shorter tetraynes and the

longer sp-chain octayne 20 shows an increasing bathoch-

romic shift of the corresponding absorption bands with in-

creasing lengths of the sp-carbon chain. This reflects the

typical behaviour of oligoynes^[4,6,7,13b]and is caused by the

narrowing of the HOMO–LUMO gap of oligoynes with in-

creasing sp-chain length (Figure 3, a).^[6,7,13b]

Palladium-Catalyzed Coupling Reactions

In an attempt to prepare the condensed bis(macrocyclic)

structures 21 by introducing tetraiodoethene (22) into two

molecules of the bis(acetylene) 10a under palladium cataly-

sis, the formation of the monomacrocyclic diyne 23, triyne

24, tetrayne 15a and the pentayne 25 was observed (0.4%,

3.8%, 1.6% yield and traces, respectively) (Scheme 5) in-

stead of the expected bis-coupled tetraethynylethene prod-

uct 21. An optimum total yield and product distribution

was obtained using catalytical amounts of CuI and

[Pd(PPh₃)₂Cl₂] and 4 equiv. of tetraiodoethene (22). Inspite

of the low yields, the individual oligoynes could be sepa-

rated by column chromatography. The compounds 23, 24

and 15a were completely characterized by ¹H and ¹³C

NMR spectroscopy, IR and UV spectroscopy and mass

spectrometry; 25 was characterized by UV/Vis and mass

spectrometry only. In order to obtain longer oligoyne struc-

tures, the C₃₂-bridged 10e was treated with tetraiodoethene

(22) under similar conditions. Only the intramolecular

homocoupling product dioxacyclodotetracontadiyne 26

and the corresponding hexayne 19b could be isolated by

column chromatography in macroscopic quantities (5 and

3% yield, respectively) (Scheme 5). The corresponding C₃₂-

Figure 3. Comparative UV/Vis spectra of a) the tetrayne 15a, hexa-

yne 19a and octayne macrocycle 20, and b) the triyne 24, pentayne

25 and heptayne macrocycle 28.

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Synthesis of Alkylene-Bridged Diphenyl-Oligoynes

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bridged triyne, tetrayne and pentayne macrocycles were de-

tected in traces only.

Scheme 6. Paladium-catalyzed coupling with diiodoacetylene (27)

and 1,4-diiodobenzene (29) to obtain heptadiyne 28 and diethyn-

ylbenzene 30. i) [Pd(PPh₃)₂Cl₂], CuI, I–CϵC–I (27), NEt₃, CH₂Cl₂.

Yield: 28 (11%); ii) [Pd(PPh₃)₂Cl₂], CuI, I–C₆H₄–I (29), NEt₃,

CHCl₃. Yield: 30 (26%).

tions (Ϸ 350–450 nm) with increasing number of triple

bonds (Figure 3, b).

Conclusion

We have presented a method for the stabilization of oli-

goynes by very long alkylene chains with up to 40 methyl-

ene groups linking the phenyl termini of the carbon rods.

At the same time we provided an access to a new class of

very large macrocyclic molecules containing segregated sp-,

sp²- and sp³-segments. The final macrocyclization step is an

alkyne homocoupling-type reaction. Despite their conju-

gated triple-bond systems, the products formed exhibited

enhanced stability against moisture and air exposure. They

were dried and stored for days, and no decomposition was

observed in solution. These oligoyne macrocycles are not

only interesting with respect to their model character of the

linear carbon allotrope carbyne. They present also new

building blocks for even more elaborated molecular archi-

tectures, which could be obtained by applying classical and

modern synthesis methods in the field of acetylene chemis-

try.^[22]Work along these lines is currently under way in our

laboratory.

Scheme 5. Palladium-catalyzed coupling with tetraiodoethene (22).

i) [Pd(PPh₃)₂Cl₂], CuI, I₂C=CI₂(22), NEt₃, CH₃CN, column

chrom. Yields: 23 (0.4%), 24 (3.8%), 15a (1.6%), 25 (traces), 26

(5%) and 19b (3%).

It was assumed that diiodoacetylene (27), obviously

formed from tetraiodoethene (22), was the active coupling

reagent in the transformations described above. Carrying

out palladium-catalyzed coupling of 27 with the bis(triyne)

17b, besides the intramolecularly coupled hexayne 19b and

traces of the corresponding octayne, the bis-heterocoupling

product heptayne 28 was isolated in a yield of 11% as an

orange solid (Scheme 6). Similarly to diiodoacetylene (27),

dihalogen-substituted aromatic compounds like the diiodo-

benzene 29 can be inserted between two terminal triple

bonds according to a Sonogashira coupling reaction.^[16]

Experimental Section

General Remarks

Chemicals: All chemicals were obtained from Aldrich, Fluka,

Sigma, Acros Organics and Lancaster, the solvents purified by dis-

tillation. All reactions were carried out under protective atmo-

sphere and in dry solvents. Thin Layer Chromatography (TLC):

Riedel-de Haën silica gel 60 F₂₅₄aluminum foils, detection: UV

Treatment of the bis-ethynylbenzene 10a with 1,4-diiodo- lamp or 10% aqueous KMnO₄solution. High-Performance Liquid

Chromatography (HPLC): Shimadzu Liquid Chromatograph LC-

8A, Diode Array Detector SPD-M 10A, UV Detector SPD-M

10A, Auto Injector Sil-10A, Selection Valve VFCV-10AL, Fraction

Collector FRC-10A. Analytical Columns: Cosmosil. Preparative

Columns: Cosmosil. NMR Spectra: JEOL JNM EX 400, JEOL

JNM GX 400 and JEOL 500. The chemical shifts are given in

[ppm] relative to TMS. The spin coupling patterns are indicated as

s (singlet), d (doublet), t (triplet), q (quadruplet), m (multiplet),

and br. (broad, for unresolved signals). UV/Vis Spectra: Shimadzu

UV-3102 PC, UV/Vis-NIR Scanning Spectrophotometer. IR Spec-

benzene (29) at 50 °C in the presence of [Pd(PPh₃)₂Cl₂], CuI

and NEt₃afforded the p-phenylene-interlinked macrocycle

30 as a white solid in 26% yield (Scheme 6). This last reac-

tion opens synthetic routes to a defined interruption of the

sp-conjugation of oligoynes and consequently to tune the

spectroscopic and electronic features of polyynes.

As in the case of the tetrayne 15a, hexayne 19a and the

octayne 20 (Figure 3, a), respectively, the electronic absorp-

tion spectra of the triyne 23, pentayne 24 and heptayne 28

reveal a successive bathochromic shift of the π,π*-transi- tra: Bruker FT-IR Vector 22, KBr pellets or thin film (NaCl plates).

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C. Klinger, O. Vostrowsky, A. Hirsch

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Mass Spectra: Micromass Zabspec, FAB (LSIMS) mode (3-ni-

trobenzyl alcohol). Elementary analysis (C, H, N) succeeded by

combustion and gas chromatographical analysis with an EA 1110

CHNS analyser (CE Instruments).

Na₂SO₄and evaporation of the solvent followed. The remaining

crude mixture was dissolved in THF (140 mL) under reflux, and

by subsequent cooling to 4 °C, the pure product 5c crystallized as

a white powder (7.57 g, 55%). ¹H NMR (400 MHz, CDCl₃, 25 °C):

δ = 4.55 (m, 2 H, CH), 3.88–3.812 (m, 2 H, CH₂), 3.73–3.68 (m, 2

H, CH₂), 3.49–3.45 (m, 2 H, CH₂), 3.38–3.33 (m, 2 H, CH₂), 1.85–

1.78 (m, 2 H, CH₂), 1.73–1.66 (m, 2 H, CH₂), 1.59–1.50 (m, 12 H,

CH₂), 1.23 (br. s, 72 H, CH₂) ppm. ¹³C NMR (100.5 MHz, CDCl₃,

25 °C): δ = 98.8 (2 C, CH), 67.7 (2 C, CH₂), 62.3 (2 C, CH₂), 30.9

(2 C, CH₂), 29.9 (2 C, CH₂), 29.8 (30 C, CH₂), 29.7 (2 C, CH₂),

29.6 (2 C, CH₂), 26.4 (2 C, CH₂), 25.6 (2 C, CH₂), 19.8 (2 C,

Synthesis of the Protective Bis(benzaldehyde) Units 8a–f

α,ω-Dibromoalkanes 1a–f

1,12-Dibromododecane (1a), 1,14-Dibromotetradecane (1b), 1,16-Di-

bromohexadecane (1c) and 1,20-Dibromoeicosane (1d): The α,ω-di-

bromoalkanes 1a–c were obtained by conventional reduction of the

corresponding dicarboxylic acids with LiAlH₄and subsequent bro-

mination with HBr. 1,20-Dibromoeicosane (1d) was yielded from

1-bromo-6-(tetrahydropyranyloxy)hexane (2a) by reaction with Mg

turnings to the organomagnesium compound 3a and subsequent

Grignard reaction with 1,8-diiodooctane (4) according to ref.^[9]The

bis-THP ether 5a was converted into 1d by bromination with tetra-

bromohexadienone 6 according to Tanaka and Oritani.^[9,17]

CH ) ppm. FT-IR (KBr): ν = 2923, 2853, 1470, 1357, 1265, 1129,

˜

2

1073, 1032, 972, 905, 872, 813, 722 cm^–1. C₅₀H₉₈O₄(763.28): calcd.

C 78.67, H 12.94; found C 78.64, H 13.07.

1,32-Dibromodotriacontane (1e): Triphenylphosphane (7.78 g,

29.70 mmol) was dissolved in CH₂Cl₂(16 mL), cooled to 0 °C, and

2,4,4,6-tetrabromo-2,5-cyclohexadienone (6, 12.18 g, 29.70 mmol)

1,32-Bis(tetrahydropyranyloxy)dotriacontane (5b):^[9]Magnesium was added and the mixture stirred for 30 min. When the yellow

turnings (2.54 g, 104.48 mmol) together with dry THF were placed

in a 1-L three-necked flask, so that the metal was covered by the

solvent. Under vigorous stirring thoroughly dried 1-bromo-6-

(tetrahydropyranyloxy)dodecane (2b) (2.50 g, 7.16 mmol) was

added, while the mixture became warm and turbid. Immediately

further 2b (25.22 g, 72.26 mmol), diluted in 330 mL dry THF, was

added dropwise, so that the solvent was kept at calm boiling tem-

perature. When the addition was complete, the solution of 3b was

heated for 2 h under reflux and subsequently cooled to –15 °C. A

color almost had disappeared, bis-THP ether 5b (4.39 g,

6.75 mmol) was added and the reaction mixture was stirred for an-

other 14 h at room temp. Subsequently the solvent was distilled

off, and the remaining solid crude product was heated in ethanol

(100 mL) under reflux for 1 h until all substances got dissolved.

When cooling to 4 °C, the pure dibromoalkane 1e crystallized

(3.90 g, 95%) as a white powder. ¹H NMR (400 MHz, CDCl₃,

25 °C): δ = 3.39 (t, ³J = 6.9 Hz, 4 H, OCH₂), 1.83 (m, 4 H,

OCH₂CH₂), 1.39 (m, 4 H, OCH₂CH₂CH₂), 1.23 (s, 52 H,

0.2  solution of Li₂CuCl₄(6.7 mL, 1.34 mmol) in THF and 1,8- CH₂) ppm. ¹³C NMR (100.5 MHz, CDCl₃, 25 °C): δ = 34.1 (2 C,

diiodooctane (4, 11.35 g, 31.01 mmol), dissolved in THF (40 mL),

were added. After 30 min the cooling bath was removed, and the

reaction mixture was stirred for additional 18 h. To the resulting

dark suspension a saturated aqueous solution of ammonium ace-

tate (350 mL) was added and stirred for another 30 min. The layers

were separated and the aqueous layer extracted twice with diethyl

ether (200 mL each). The combined organic layers were washed

twice with water (300 mL each), dried with Na₂SO₄and concen-

trated to dryness. The crude product was dissolved in boiling THF

(140 mL) and crystallized after cooling to 4 °C. 5b was isolated as

a white powder (15.32 g, 76%). ¹H NMR (300 MHz, CDCl₃,

25 °C): δ = 4.51 (m, 2 H, CH), 3.82–3.80 (m, 2 H, CH₂), 3.67–3.62

(m, 2 H, CH₂), 3.44–3.43 (m, 2 H, CH₂), 3.35–3.27 (m, 2 H, CH₂),

1.80–1.70 (m, 2 H, CH₂), 1.64–1.63 (m, 2 H, CH₂), 1.54–1.45 (m,

12 H, CH₂), 1.18 (br. s, 56 H, CH₂) ppm. ¹³C NMR (100.5 MHz,

CDCl₃, 25 °C): δ = 98.8 (2 C, CH), 67.7 (2 C, CH₂), 62.3 (2 C,

CH₂), 30.8 (2 C, CH₂), 29.8 (2 C, CH₂), 29.7 (22 C, CH₂), 29.6 (2

C, CH₂), 29.5 (2 C, CH₂), 26.2 (2 C, CH₂), 25.5 (2 C, CH₂), 19.7

CH₂), 32.8 (2 C, CH₂), 29.7 (18 C, CH₂), 29.6 (2 C, CH₂), 29.5 (2

C, CH₂), 29.4 (2 C, CH₂), 28.8 (2 C, CH₂), 28.2 (2 C, CH₂) ppm.

IR (KBr): ν = 2923, 2851, 1470, 1303, 1268, 1235, 1202, 1008, 719,

˜

643 cm^–1. C₃₂H₆₄Br₂(608.66): calcd. C 63.14, H 10.60; found C

62.73, H 10.49.

1,40-Dibromotetracontane (1f): Similar to the synthesis of 1e, a mix-

ture of triphenylphosphane (4.69 g, 17.90 mmol) and 2,4,4,6-tetra-

bromo-2,5-cyclohexadienone (6, 7.34 g, 17.90 mmol) in CH₂Cl₂

(45 mL) was treated with bis-THP ether 5c (3.10 g, 4.07 mmol).

After stirring for 16 h and work up as for 1e in boiling ethanol

(650 mL), the product 1f crystallized as a white powder (2.80 g,

96%). ¹H NMR (400 MHz, CDCl₃, 40 °C): δ = 3.38 (t, ³J = 6.8 Hz,

4 H, Br–CH₂), 1.83 (m, 4 H, Br–CH₂–CH₂), 1.45 (m, 4 H,

BrCH₂CH₂CH₂), 1.24 (s, 68 H, CH₂) ppm. ¹³C NMR (100.5 MHz,

CDCl₃, 50 °C): δ = 33.9 (2 C, BrCH₂), 32.9 (2 C, BrCH₂CH₂), 29.7

(22 C, CH₂), 29.5 (2 C, CH₂), 28.7 (2 C, CH₂), 28.2 (2 C,

CH ) ppm. IR (KBr): ν = 2929, 2850, 1468, 1195, 1115, 724, 646,

˜

2

544 cm^–1. C₄₀H₈₀Br₂(720.87): calcd. C 66.65, H 11.19; found C

(2 C, CH ) ppm. IR (KBr): ν =2960, 2848, 2788, 2655, 1465, 1442,

˜

2

66.23, H 10.99.

1352, 1315, 1260, 1207, 1197, 1127, 1073, 1030, 980, 907, 872, 813,

722, 669, 576, 543 cm^–1. C₄₂H₈₂O₄(651.08): calcd. C 77.47, H

12.69; found C 77.57, H 12.84.

Bis(benzaldehydes) 8a–f

1,12-Bis(4-tert-butyl-2-formylphenyloxy)dodecane (8a): To a solu-

tion of 5-tert-butyl-2-hydroxybenzaldehyde (7)^[18](10.00 g,

56.18 mmol) in DMF (250 mL) K₂CO₃(23.15 g, 167.75 mmol) was

added. To the resulting yellow suspension 1,12-dibromododecane

(1a, 9.21 g, 28.08 mmol) was added and heated to 80 °C. The

course of the reaction was monitored by means of TLC (CH₂Cl₂,

R_f= 0.55). After 16 h the mixture was cooled to room temp. and

diethyl ether (300 mL) and water (250 mL) was added. The organic

layer was separated, the aqueous phase was extracted twice with

diethyl ether (250 mL each) and the combined organic phases

washed with water (300 mL). After drying with Na₂SO₄the solvent

was distilled off in vacuo and the remaining crude mixture dis-

1,40-Bis(tetrahydropyranyloxy)tetracontane (5c): According to the

synthesis of 5b, magnesium turnings (1.56 g, 64.18 mmol) were

treated with 1-bromo-14-(tetrahydropyranyloxy)tetradecane (2c)

(2.00 g, 5.31 mmol). Additional THP ether 2c (18.39 g,

48.79 mmol) in THF (160 mL) was added and the mixture kept at

reflux. When the addition was complete, the solution of 3c was

heated and cooled as described in the paragraph above for 5b. Sub-

sequent treatment with a 0.2  solution of Li₂CuCl₄in THF

(4.1 mL, 0.82 mmol) and 1,12-dibromododecane (1a, 5.93 g,

18.08 mmol) after stirring for 18 h led to bis-THP ether 5c. After

workup with an aqueous solution of ammonium acetate, extraction

with CH₂Cl₂(150 mL each, twice), washing with water (250 mL) solved in boiling diethyl ether (600 mL). Upon cooling, the product

and saturated aqueous NaCl solution (250 mL), drying with

8a crystallized as a white solid (11.02 g, 75%). ¹H NMR (400 MHz,

1514

www.eurjoc.org

Eur. J. Org. Chem. 2006, 1508–1524

Synthesis of Alkylene-Bridged Diphenyl-Oligoynes

FULL PAPER

CDCl₃, 25 °C): δ = 10.49 (s, 2 H, CHO), 7.82 (d, ⁴J = 2.6 Hz, 2 H,

ArH), 7.54 (dd, J = 2.7 Hz, J = 8.8 Hz, 2 H, ArH), 6.89 (d, J = 1246, 1192, 1140, 1098, 1053, 1020, 987, 935, 909, 839, 824, 729,

8.8 Hz, 2 H, ArH), 4.03 (t, ³J = 6.4 Hz, 4 H, OCH₂), 1.81 (m, 4 679, 652, 601, 571, 501 cm^–1. UV/Vis (CH₂Cl₂): λ_max= 256,

H, OCH₂CH₂), 1.46 (m, 4 H, OCH₂CH₂CH₂), 1.24–1.35 (m, 12 H, 329 nm. MS (FAB): m/z = 579 [M⁺]. C₃₈H₅₈O₄(578.84): calcd. C

2850, 1679, 1608, 1579, 1498, 1472, 1414, 1389, 1364, 1295, 1266,

4

3

CH₂) and 1.28 [s, 18 H, C(CH₃)₃] ppm. ¹³C NMR (100.5 MHz,

CDCl₃, 25 °C): δ = 189.9 (2 C, CHO), 159.4 (2 C, ArC), 143.1 (2

C, ArC), 133.0 (2 C, ArCH), 124.4 (2 C, ArCH), 124.1 (2 C, ArC),

112.2 (2 C, ArCH), 68.6 (2 C, OCH₂), 34.3 [2 C, C(CH₃)₃], 31.4 [6

C, C(CH₃)₃], 29.6 (4 C, CH₂), 29.4 (2 C, CH₂), 26.2 (2 C, CH₂),

78.84, H 10.10; found C 78.44, H 10.01.

1,20-Bis(4-tert-butyl-2-formylphenyloxy)eicosane (8d): The bis(benz-

aldehyde) 8d was obtained in analogy of the synthesis of 8c, from

1,20-dibromoeicosane (1d, 2.97 g, 6.75 mmol), 5-tert-butyl-2-hy-

droxybenzaldehyde (7, 2.40 g, 13.49 mmol) and K₂CO₃(5.58 g,

40.43 mmol) in DMF (60 mL). After a reaction time of 18 h, TLC

monitoring (ethyl acetate/petroleum ether, 5:95, R_f= 0.21) revealed

complete transformation. The mixture was cooled and water

(250 mL) and diethyl ether (250 mL) were added. After separating

the layers, the aqueous layer was extracted with diethyl ether (three

times, 150 mL each), and the combined ether phases were washed

with water (twice, 300 mL each) and saturated aqueous solution of

NaCl (300 mL). After drying with Na₂SO₄, the solvent was distilled

off and the crude mixture dissolved in boiling diethyl ether

(40 mL). After subsequent cooling to –30 °C the product 8d crys-

tallized as a white powder (3.63 g, 85%). ¹H NMR (400 MHz,

CDCl₃, 25 °C): δ = 10.60 (s, 2 H, CHO), 7.64 (d, ⁴J = 2.2 Hz, 2 H,

26.1 (2 C, CH ) ppm. FT-IR (KBr): ν = 2921, 2852, 1681, 1607,

˜

2

1579, 1497, 1471, 1415, 1388, 1364, 1292, 1266, 1246, 1191, 1138,

1098, 1042, 1001, 934, 819, 733, 679, 651, 600, 570 cm^–1. UV/Vis

(CH₂Cl₂): λ_max= 256, 329 nm. MS (FAB): m/z = 523 [M⁺].

C₃₄H₅₀O₄(522.74): calcd. C 78.12, H 9.64; found C 77.94, H 9.94.

1,14-Bis(4-tert-butyl-2-formylphenyloxy)tetradecane (8b): Accord-

ing to the same procedure as applied for the synthesis of 8a, 5-tert-

butyl-2-hydroxybenzaldehyde (7) (5.00 g, 28.09 mmol) was treated

with 1,14-dibromotetradecane (1b, 5.00 g, 14.04 mmol) in DMF

(100 mL). After heating for 16 h (TLC control: CH₂Cl₂/hexane,1:1,

R_f= 0.23) and cooling, water (200 mL) and CH₂Cl₂(200 mL) was

added. The aqueous layer was extracted with CH₂Cl₂(200 mL) and

the combined organic layers washed and dried. After work up sim-

ilar as for 8a, from boiling diethyl ether (200 mL) and cooling to

–30 °C the white solid 8b crystallized (5.76 g, 75%). ¹H NMR

4

3

ArH), 7.37 (dd, J = 2.2 Hz, J = 8.8 Hz, 2 H, ArH), 6.71 (d, J =

8.8 Hz, 2 H, ArH), 3.85 (t, ³J = 6.3 Hz, 4 H, OCH₂), 1.61 (m, 4

H, OCH₂CH₂), 1.28 (m, 4 H, OCH₂CH₂CH₂), 1.10 (br. s, 52 H,

CH₂), 1.06 [s, 18 H, C(CH₃)₃] ppm. ¹³C NMR (100.5 MHz, CDCl₃,

25 °C): δ = 190.2 (2 C, CHO), 159.6 (2 C, ArC), 143.3 (2 C, ArC),

133.1 (2 C, ArCH), 124.6 (2 C, ArCH), 124.2 (2 C, ArC), 112.3 (2

C, ArCH), 68.5 (2 C, OCH₂), 34.2 [2 C, C(CH₃)₃], 31.3 (8 C, CH₂),

29.7 [6 C, C(CH₃)₃], 29.6 (2 C, CH₂), 29.5 (2 C, CH₂), 29.3 (2 C,

4

(400 MHz, CDCl₃, 25 °C): δ = 10.47 (s, 2 H, CHO), 7.82 (d, J =

3

4

2.6 Hz, 2 H, ArH), 7.54 (dd, J = 8.7 Hz, J = 2.6 Hz, 2 H, ArH),

3

6.89 (d, J = 8.7 Hz, 2 H, ArH), 4.03 (t, J = 6.4 Hz, 4 H, OCH₂),

1.81 (m, 4 H, OCH₂CH₂), 1.44 (m, 4 H, OCH₂CH₂CH₂), 1.33–

1.25 (m, 16 H, CH₂), 1.28 [s, 18 H, C(CH₃)₃] ppm. ¹³C NMR

(100.5 MHz, CDCl₃, 25 °C): δ = 190.2 (2 C, CHO), 159.6 (2 C,

ArC), 143.3 (2 C, ArC), 133.1 (2 C, ArCH), 124.6 (2 C, ArCH),

124.2 (2 C, ArC), 112.3 (2 C, ArCH), 68.6 (2 C, OCH₂), 34.2 [2 C,

C(CH₃)₃], 31.3 [6 C, C(CH₃)₃], 29.6 (4 C, CH₂), 29.5 (2 C, CH₂),

29.3 (2 C, CH₂), 29.1 (2 C, CH₂), 26.1 (2 C, CH₂) ppm. IR (KBr):

CH ), 29.1 (2 C, CH ), 26.0 (2 C, CH ) ppm. IR (KBr): ν = 3442,

˜

2

2961, 2920, 2850, 2754, 1680, 1606, 1580, 1497, 1468, 1413, 1389,

1366, 1292, 1265, 1243, 1192, 1138, 1099, 1028, 935, 820, 722, 679,

651, 600, 568 cm^–1. UV/Vis (CH₂Cl₂): λ_max= 256, 330 nm. MS

(FAB): m/z = 636 [M]⁺. C₄₂H₆₆O₄(634.95): calcd. C 79.44, H 10.48;

found C 79.47, H 10.57.

ν = 2920, 2850, 1680, 1608, 1579, 1498, 1471, 1414, 1389, 1364,

˜

1295, 1266, 1246, 1191, 1139, 1098, 1047, 1014, 935, 835, 819, 731,

679, 651, 600, 571 cm^–1. UV/Vis (CH₂Cl₂): λ_max= 256, 330 nm. MS

(FAB): m/z = 551 [M⁺]. C₃₆H₅₄O₄(550.79): calcd. C 78.50, H 9.88;

found C 78.07, H 9.88.

1,32-Bis(4-tert-butyl-2-formylphenyloxy)dotriacontane (8e): 5-tert-

Butyl-2-hydroxybenzaldehyde (7, 2.90 g, 16.28 mmol), dissolved in

DMF (150 mL), and 1,32-dibromodotriacontane (1e, 4.95 g,

8.14 mmol) was heated to 80 °C to complete dissolution. After ad-

dition of K₂CO₃(6.78 g, 49.14 mmol) and stirring for 15 h, water

1,16-Bis(4-tert-butyl-2-formylphenyloxy)hexadecane (8c): Accord-

ing to the synthesis of 8a, a mixture of the hydroxybenzaldehyde 7

(1.00 g, 5.60 mmol), 1,16-dibromohexadecane (1c, 1.08 g, (250 mL) and CH₂Cl₂(250 mL) were added and the layers were

2.81 mmol) and K₂CO₃(2.33 g, 16.88 mmol) was heated for 16 h allowed to separate. The aqueous layer was extracted with CH₂Cl₂

at 80 °C (TLC monitoring: CH₂Cl₂/hexane, 7:3, R_f= 0.33). After

addition of additional dibromohexadecane 1c (54 mg, 0.14 mmol)

and heating for two more hours, working up succeeded with diethyl

ether and water (150 mL each). The aqueous layer was separated,

extracted with diethyl ether (3 × 100 mL), and the combined or-

ganic phases were washed with water (2 × 200 mL) and saturated

aqueous NaCl solution (200 mL). After drying with Na₂SO₄the

final purification was performed by column chromatography (silica

(twice, 200 mL each), the organic phases combined, washed with

water (twice, 250 mL each) and dried with Na₂SO₄. After filtering

off the Na₂SO₄, the solution was concentrated and the crude mix-

ture redissolved in boiling diethyl ether (350 mL). After cooling the

solution to –30 °C, 8e was isolated by precipitation as a white pow-

1

der (5.90 g, 90%). H NMR (400 MHz, CDCl₃, 25 °C): δ = 10.49

(s, 2 H, CHO), 7.83 (d, ⁴J = 2.2 Hz, 2 H, ArH), 7.54 (dd, ⁴J =

3

2.2 Hz, J = 8.8 Hz, 2 H, ArH), 6.89 (d, J = 8.8 Hz, 2 H, ArH),

3

gel, CH₂Cl₂/hexane, 1:1 Ǟ 7:3), and the white solid 8c (1.26 g,

4.03 (t, J = 6.3 Hz, 4 H, OCH₂), 1.81 (m, 4 H, OCH₂CH₂), 1.44

1

78%) was isolated. H NMR (400 MHz, CDCl₃, 25 °C): δ = 10.49 (m, 4 H, OCH₂CH₂CH₂), 1.29 [s, 18 H, C(CH₃)₃], 1.23 (br. s, 52

(s, 2 H, CHO), 7.82 (d, ⁴J = 2.7 Hz, 2 H, ArH), 7.54 (dd, ³J =

H, CH₂) ppm. ¹³C NMR (100.5 MHz, CDCl₃, 25 °C): δ = 190.2 (2

C, CHO), 159.6 (2 C, ArC), 143.2 (2 C, ArC), 133.1 (2 C, ArCH),

124.6 (2 C, ArCH), 124.2 (2 C, ArC), 112.2 (2 C, ArCH), 68.5 (2

C, OCH₂), 34.2 [2 C, C(CH₃)₃], 31.3 [6 C, C(CH₃)₃], 29.9 (22 C,

4

3

8.7 Hz, J = 2.6 Hz, 2 H, ArH), 6.89 (d, J = 8.8 Hz, 2 H, ArH),

3

4.03 (t, J = 6.4 Hz, 4 H, OCH₂), 1.81 (m, 4 H, OCH₂CH₂), 1.46

(m, 4 H, OCH₂CH₂CH₂), 1.24–1.33 (m, 12 H, CH₂), 1.28 [s, 18 H,

C(CH₃)₃] ppm. ¹³C NMR (100.5 MHz, CDCl₃, 25 °C): δ = 189.9 CH₂), 29.6 (2 C, CH₂), 29.3 (2 C, CH₂), 29.2 (2 C, CH₂), 26.0 (2

(2 C, CHO), 159.5 (2 C, ArC), 143.1 (2 C, ArC), 133.00 (2 C, C, CH ) ppm. IR (KBr): ν = 3442, 2919, 2849, 2758, 1680, 1608,

˜

2

ArCH), 124.5 (2 C, ArCH), 124.1 (2 C, ArC), 112.2 (2 C, ArCH), 1579, 1498, 1472, 1414, 1389, 1364, 1295, 1266, 1245, 1192, 1138,

68.6 (2 C, OCH₂), 34.3 [2 C, C(CH₃)₃], 31.4 [6 C, C(CH₃)₃], 29.7 1098, 1036, 1008, 934, 909, 834, 819, 721, 678, 651, 600, 570 cm^–1.

(2 C, CH₂), 29.67 (4 C, CH₂), 29.65 (2 C, CH₂), 29.4 (2 C, CH₂),

29.2 (2 C, CH ), 26.2 (2 C, CH ) ppm. IR (KBr): ν = 2951, 29120,

UV/Vis (CH₂Cl₂): λ_max= 251, 330 nm. MS (FAB): m/z = 804 [M]⁺.

C₅₄H₉₀O₄(803.26): calcd. 80.74, H 11.29; found 80.21, H 11.46.

˜

2

Eur. J. Org. Chem. 2006, 1508–1524

www.eurjoc.org

1515

C. Klinger, O. Vostrowsky, A. Hirsch

FULL PAPER

1,40-Bis(4-tert-butyl-2-formylphenyloxy)tetracontane (8f): The di-

phenyl ether 8f was was obtained by heating 1,40-dibromotetracon-

tane (1f, 81 g, 5.29 mmol) and 5-tert-butyl-2-hydroxybenzaldehyde

and water (300 mL), washing with water (twice, 400 mL), drying

with Na₂SO₄and column chromatography (silica gel, CH₂Cl₂/hex-

ane, 1:1). The bridged distyryl compound 9b was isolated as a col-

(7, 1.88 g, 10.58 mmol) in DMF (80 mL) at 90 °C. After the ad- orless oil (8.30 g, 9.63 mmol). ¹H NMR (400 MHz, CDCl₃, 25 °C):

4

dition of K₂CO₃(4.41 g, 31.96 mmol) and heating for 18 h, TLC

analysis (CH₂Cl₂/hexane, 1:1, R_f= 0.33) revealed complete conver-

sion. The mixture was cooled to room temperature, treated with

water (300 mL) and CH₂Cl₂(300 mL), and the layers were allowed

to separate. The aqueous layer was extracted with CH₂Cl₂(twice,

150 mL each), the combined CH₂Cl₂phases were washed with

water (twice, 350 mL each) and dried with Na₂SO₄according to

the preparation of 8e. The solvent was removed and the remaining

solid was dissolved in 1 L of boiling diethyl ether. By precipitation

at –30 °C, product 8f was obtained (4.37 g, 90%) as a white powder.

δ = 7.74 (d, J = 2.6 Hz, 2 H, ArH), 7.61 (s, 2 H, Br₂C=CH), 7.27

3

4

3

(dd, J = 8.7 Hz, J = 2.5 Hz, 2 H, ArH), 6.76 (d, J = 8.7 Hz, 2

H, ArH), 3.93 (t, ³J = 6.6 Hz, 4 H, OCH₂), 1.77 (m, 4 H,

OCH₂CH₂), 1.41 (m, 4 H, OCH₂CH₂CH₂), 1.24–1.33 (m, 16 H,

CH₂), 1.27 [s, 18 H, C(CH₃)₃] ppm. ¹³C NMR (100.5 MHz, CDCl₃,

25 °C): δ = 153.9 (2 C, ArC), 142.5 (2 C, ArC), 133.4 (2 C, ArCH),

126.4 (4 C, ArCH and Br₂C=CH), 123.8 (2 C, ArC), 111.1 (2 C,

ArCH), 88.9 (2 C, Br₂C=CH), 68.5 (2 C, OCH₂), 34.2 [2 C, C(CH₃)₃],

31.4 [6 C, C(CH₃)₃], 29.7 (4 C, CH₂), 29.6 (2 C, CH₂), 29.3 (2 C,

CH ), 29.2 (2 C, CH ), 26.1 (2 C, CH ) ppm. IR (NaCl): ν = 2926,

˜

2

¹H NMR (400 MHz, CDCl₃, 25 °C): δ = 10.49 (s, 2 H, CHO), 7.83 2854, 1606, 1577, 1494, 1468, 1392, 1363, 1304, 1251, 1201, 1136,

4

3

(d, J = 2.2 Hz, 2 H, ArH), 7.54 (dd, J = 2.2 Hz, J = 8.8 Hz, 2 1106, 1026, 939, 900, 842, 811, 737, 673, 629, 603, 581 cm^–1. UV/

H, ArH), 6.89 (d, J = 8.8 Hz, 2 H, ArH), 4.03 (t, J = 6.3 Hz, 4 Vis (CH₂Cl₂): λ_max= 259, 307 nm. MS (FAB): m/z = 862 [M⁺].

3

H, OCH₂), 1.81 (m, H, OCH₂CH₂), 1.45 (m, H, C₃₈H₅₄Br₄O₂(862.48): calcd. C 52.92, H 6.31; found C 52.45, H

4

OCH₂CH₂CH₂), 1.29 [s, 18 H, C(CH₃)₃], 1.23 (br. s, 68 H, 6.84.

CH₂) ppm. ¹³C NMR (100.5 MHz, CDCl₃, 25 °C): δ = 189.9 (2 C,

1,16-Bis[4-tert-butyl-2-(2,2-dibromoethenyl)phenyloxy]hexadecane

CHO), 159.5 (2 C, ArCO), 143.1 [2 C, ArCC(CH₃)₃], 133.0 (2 C,

ArCH), 124.5 (2 C, ArCH), 124.1 (2 C, ArCCHO), 112.2 (2 C,

ArCH), 68.6 (2 C, OCH₂), 34.3 [2 C, C(CH₃)₃], 31.4 [6 C, C(CH₃)₃],

29.8 (30 C, CH₂), 29.7 (2 C, CH₂), 29.4 (2 C, CH₂), 29.2 (2 C,

(9c): The preparation of the C₁₆-bridged compound 9c was

achieved by preparing a mixture of CBr₄(3.21 g, 9.67 mmol) in

CH₂Cl₂(16 mL) and PPh₃(5.07 g, 19.34 mmol) at 0 °C. To this

yellow-orange suspension a solution of 8c (1.22 g, 2.10 mmol) in

CH₂Cl₂(25 mL) was added dropwise. After 20 min, the reaction

was complete (TLC: CH₂Cl₂, R_f= 0.70), and water (300 mL) and

CH₂Cl₂(150 mL) were added. The aqueous layer was extracted

twice with CH₂Cl₂(150 mL each), the combined organic layers

dried with Na₂SO₄and the product 9c isolated by column

chromatography (silica gel, CH₂Cl₂) as a white solid (1.86 g, quan-

CH ), 26.2 (2 C, CH ) ppm. IR (KBr): ν = 3450, 2963, 2919, 2850,

˜

2

2756, 1680, 1606, 1497, 1473, 1389, 1365, 1263, 1192, 1097, 1027,

1008, 804, 719 cm^–1. UV/Vis (CH₂Cl₂): λ_max= 255, 330 nm. MS

(FAB): m/z = 916 [M]⁺. C₆₂H₁₀₆O₄(915.47): calcd. C 81.34, H

11.67; found C 80.77, H 11.80.

Synthesis of Tetrayne Macrocycles 15a–c

1

4

titatively). H NMR (400 MHz, CDCl₃, 25 °C): δ = 7.74 (d, J =

2.2 Hz, 2 H, ArH), 7.61 (s, 2 H, Br₂C=CH), 7.27 (dd, ³J = 8.8 Hz,

1,12-Bis[4-tert-butyl-2-(2,2-dibromoethenyl)phenyloxy]dodecane

(9a): CBr₄(19.90 g, 59.94 mmol) was dissolved in CH₂Cl₂(100 mL)

and the solution cooled to 0 °C. PPh₃(31.41 g, 119.88 mmol) was

added to this cold solution. Subsequently, a solution of 8a (7.12 g,

13.62 mmol) in CH₂Cl₂(200 mL) was added dropwise, and the re-

action was completed after 10 min (TLC monitoring: CH₂Cl₂/hex-

ane, 2:8, R_f= 0.68). Water (250 mL) and CH₂Cl₂(250 mL) was

added and the layers separated. The aqueous layer was extracted

three times with CH₂Cl₂(100 mL each) and the organic layers were

combined. After drying with Na₂SO₄and column chromatography

(CH₂Cl₂/hexane, 2:8) a clear and colorless oil was isolated (10.79 g,

95 %). ¹H NMR (400 MHz, CDCl₃, 25 °C): δ = 7.74 (d, ⁴J =

2.5 Hz, 2 H, ArH), 7.61 (s, 2 H, Br₂C=CH), 7.27 (dd, ³J = 8.6 Hz,

⁴J = 2.2 Hz, 2 H, ArH), 6.76 (d, J = 8.8 Hz, 2 H, ArH), 3.93 (t,

3

³J = 6.3 Hz, 4 H, OCH₂), 1.77 (m, 4 H, OCH₂CH₂), 1.43 (m, 4 H,

OCH₂CH₂CH₂), 1.26–1.33 (m, 20 H, CH₂), 1.29 [s, 18 H, C(CH₃)₃]

ppm. ¹³C NMR (100.5 MHz, CDCl₃, 25 °C): δ = 153.9 (2 C, ArC),

142.5 (2 C, ArC), 133.3 (2 C, ArCH), 126.4 (4 C, ArCH and

Br₂C=CH), 123.8 (2 C, ArC), 111.1 (2 C, ArCH), 88.9 (2 C,

Br₂C=CH), 68.5 (2 C, OCH₂), 34.2 [2 C, C(CH₃)₃], 31.4 [6 C,

C(CH₃)₃], 29.7 (6 C, CH₂), 29.6 (2 C, CH₂), 29.3 (2 C, CH₂), 29.2

(2 C, CH ), 26.1 (2 C, CH ) ppm. IR (NaCl): ν = 2925, 2854, 1606,

˜

2

1578, 1494, 1468, 1392, 1363, 1304, 1252, 1202, 1137, 1106, 1027,

939, 901, 843, 811, 737, 673, 630, 603 cm^–1. UV/Vis (CH₂Cl₂):

λ_max= 259, 307 nm. MS (FAB): m/z = 890 [M⁺]. C₄₀H₅₈Br₄O₂

(890.53): calcd. C 53.95, H 6.57; found C 52.78, H 6.12.

3

⁴J = 2.5 Hz, 2 H, ArH), 6.76 (d, J = 8.7 Hz, 2 H, ArH), 3.94 (t,

³J = 6.5 Hz, 4 H, OCH₂), 1.77 (m, 4 H, OCH₂CH₂), 1.43 (m, 4 H,

OCH₂CH₂CH₂), 1.39–1.21 (m, 12 H, CH₂), 1.29 [s, 18 H, C(CH₃)₃]

ppm. ¹³C NMR (100.5 MHz, CDCl₃, 25 °C): δ = 153.9 (2 C, ArC),

142.6 (2 C, ArC), 133.4 (2 C, Br₂C=CH), 126.4 (4 C, ArCH u.

ArC), 123.8 (2 C, ArC), 111.1 (2 C, ArCH), 88.9 (2 C, Br₂C=CH),

68.5 (2 C, OCH₂), 34.2 [2 C, C(CH₃)₃], 31.4 [6 C, C(CH₃)₃], 29.6

(4 C, CH₂), 29.3 (2 C, CH₂), 29.2 (2 C, CH₂), 26.1 (2 C, CH₂) ppm.

1,12-Bis(4-tert-butyl-2-ethynylphenyloxy)dodecane (10a): Diisopro-

pylamine (4.80 g, 47.52 mmol) was dissolved in THF (120 mL), co-

oled to 0 °C, treated with a 1.6  n-butyllithium solution (30 mL,

48.00 mmol) in hexane and stirred for 1 h. Subsequently, 100 mL

of the resulting solution of LDA (0.30 , 30.00 mmol) was added

at –80 °C to 9a (5.00 g, 6.00 mmol), dissolved in THF (120 mL).

The reaction process was controlled by TLC (CH₂Cl₂/hexane, 1:1,

R_f= 0.49). After 30 min the cooling bath was removed and aqueous

HCl (10%, 200 mL) and CH₂Cl₂(200 mL) were added. After sepa-

rating the layers the aqueous layer was extracted three times with

CH₂Cl₂(150 mL each). Then the organic layers were washed with

water (200 mL) and dried with Na₂SO₄. A clear and colourless oil

was isolated by column chromatography (silica gel, CH₂Cl₂/hexane,

1:1) (2.93 g, 95%). ¹H NMR (400 MHz, CDCl₃, 25 °C): δ = 7.45

IR (NaCl): ν = 3031, 2928, 2855, 1606, 1578, 1494, 1468, 1392,

˜

1363, 1303, 1251, 1201, 1136, 1105, 1025, 938, 900, 843, 812, 737,

673, 623, 603, 581 cm^–1. UV/Vis (CH₂Cl₂): λ_max= 306, 258 nm. MS

(FAB): m/z = 834 [M⁺]. C₃₆H₅₀Br₄O₂(834.42): calcd. C 51.82, H

6.04, found C 51.89, H 6.24.

1,14-Bis[4-tert-butyl-2-(2,2-dibromoethenyl)phenyloxy]tetradecane

(9b): In analogy to the synthesis of 9a, the dibromostyrene 9b was

obtained from CBr₄(15.43 g, 46.48 mmol) in CH₂Cl₂(80 mL),

PPh₃(24.35 g, 92.94 mmol) and the dropwise addition of a solution

of 8b (5.56 g, 10.11 mmol) in CH₂Cl₂(100 mL) at 0 °C (TLC:

CH₂Cl₂, R_f= 0.87). Working up succeeded with CH₂Cl₂(200 mL)

4

3

4

(d, J = 2.6 Hz, 2 H, ArH), 7.28 (dd, J = 8.7 Hz, J = 2.6 Hz, 2

3

H, ArH), 6.78 (d, J = 8.8 Hz, 2 H, ArH), 3.99 (t, J = 6.6 Hz, 4

H, OCH₂), 3.22 (s, 2 H, CϵCH), 1.80 (m, 4 H, OCH₂CH₂), 1.44

(m, 4 H, OCH₂CH₂CH₂), 1.26 [br. s, 30 H, CH₂and C(CH₃)₃]

1516

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Eur. J. Org. Chem. 2006, 1508–1524

Synthesis of Alkylene-Bridged Diphenyl-Oligoynes

FULL PAPER

ppm. ¹³C NMR (100.5 MHz, CDCl₃, 25 °C): δ = 157.9 (2 C, ArC),

142.8 (2 C, ArC), 130.9 (2 C, ArCH), 127.0 (2 C, ArC), 111.6 (2

C, ArCH), 110.8 (2 C, ArCH), 80.7 (2 C, CϵCH), 80.3 (2 C,

C, CH ) ppm. IR (KBr): ν = 3315, 3291, 2926, 2854, 1602, 1500,

˜

2

1468, 1393, 1363, 1269, 1140, 1105, 1020, 894, 813, 635 cm^–1. UV/

Vis (CH₂Cl₂): λ_max[nm] = 241, 250, 298, 306 nm. MS (FAB):

CϵCH), 68.9 (2 C, OCH₂), 34.1 [2 C, C(CH₃)₃], 31.4 [6 C, C(CH₃)₃], m/z = 571 [M⁺]. C₄₀H₅₈O₂(570.86): calcd. C 84.15, H 10.24; found

29.7 (4 C, CH₂), 29.4 (2 C, CH₂), 29.2 (2 C, CH₂), 26.0 (2 C, C 83.79, H 10.20.

CH ) ppm. IR (NaCl): ν = 3316, 3289, 2926, 2856, 2111, 1741,

˜

2

1,12-Bis[4-tert-butyl-2-(4-trimethylsilylbutadiynyl)phenyloxy]dode-

cane (12a): CuCl (1.74 g, 17.58 mmol) and TMEDA (0.82 mg,

7.10 mmol) were dissolved in acetone (160 mL) and stirred for

50 min. Subsequently, the mixture was filtered several times until

no more precipitating solid was found in the filtrate. The filter resi-

dues were washed with acetone (5 mL each). The dark green solu-

tion was added dropwise over a period of 30 min to a solution of

(trimethylsilyl)acetylene (11; 2.29 g, 23.37 mmol) and 10a (1.00 g,

1.95 mmol) in acetone (100 mL), through which oxygen was

bubbled for 15 min. During the continuous bubbling of oxygen

through the solution, small quantities of acetone were added in

order to prevent thickening. Because there was still starting mate-

rial detectable by TLC monitoring (CH₂Cl₂/hexane, 2:8, R_f= 0.32),

an additional re-dosage of (trimethylsilyl)acetylene (11, 304 mg,

3.12 mmol) was added in three portions (76 mg, 76 mg and finally

152 mg). After 30 h stirring, to the resulting mixture HCl (10%,

120 mL), H₂O (130 mL) and hexane (150 mL) were added. Sub-

sequently, the two layers were separated, and the aqueous layer

extracted with hexane (3 × 100 mL). The combined hexane layers

1602, 1498, 1467, 1393, 1363, 1266, 1204, 1139, 1104, 1019, 895,

814, 776, 721 cm^–1. UV/Vis (CH₂Cl₂): λ_max[nm] = 241, 249, 305,

346 nm. MS (FAB): m/z = 515 [M⁺]. C₃₆H₅₀O₂(514.76): calcd. C

83.99, H 9.79; found C 84.18, H 10.11.

1,14-Bis(4-tert-butyl-2-ethynylphenyloxy)tetradecane (10b): The bis-

(acetylene)-terminated compound 10b was obtained from a solu-

tion of diisopropylamine (11.17 g, 110.59 mmol) in THF (280 mL)

and a 1.6  solution of n-butyllithium (69 mL, 110.40 mmol). The

resulting 0.3  LDA solution (230 mL, 69.00 mmol) was added

dropwise to a solution of 9b (8.18 g, 9.49 mmol) in THF (180 mL)

at –80 °C. After 20 min (TLC: CH₂Cl₂/hexane, 3:7, R_f= 0.28) no

more starting material was observed. The cooling bath was re-

moved and 200 mL 10% aqueous HCl, 100 mL water and 200 mL

hexane were added. The aqueous layer was extracted with hexane

(100 mL) and the combined organic layers washed three times with

water (150 mL each) and dried with Na₂SO₄. Purification was

achieved by column chromatography (silica gel, ethyl acetate/hex-

ane, 1:9) and yielded 10b as a clear oil (4.63 g, 90%). ¹H NMR

(400 MHz, CDCl₃, 25 °C): δ = 7.44 (d, ⁴J = 2.6 Hz, 2 H, ArH), were washed with aqueous HCl (10%, 100 mL) and water (2 ×

7.28 (dd, ³J = 8.7 Hz, ⁴J = 2.6 Hz, 2 H, ArH), 6.78 (d, ³J = 8.8 Hz,

100 mL), and dried with Na₂SO₄. By column chromatography (sil-

2 H, ArH), 3.99 (t, ³J = 6.6 Hz, 4 H, OCH₂), 3.22 (s, 2 H, CϵCH), ica gel, CH₂Cl₂/cyclohexane, 1:9) 12a was obtained as a white solid

1

1.80 (m, 4 H, OCH₂CH₂), 1.45 (m, 4 H, OCH₂CH₂CH₂), 1.32– (772 mg, 56%). H NMR (400 MHz, CDCl₃, 25 °C): δ = 7.43 (d,

1.25 (m, 16 H, CH₂), 1.26 [s, 18 H, C(CH₃)₃] ppm. ¹³C NMR

⁴J = 2.6 Hz, 2 H, Ar–H), 7.27 (dd, J = 8.7 Hz, J = 2.6 Hz, 2 H,

3

4

3

(100.5 MHz, CDCl₃, 25 °C): δ = 158.0 (2 C, ArC), 142.9 (2 C, ArH), 6.75 (d, J = 8.8 Hz, 2 H, ArH), 3.97 (t, J = 6.7 Hz, 4 H,

ArC), 131.0 (2 C, ArCH), 127.1 (2 C, ArC), 111.6 (2 C, ArCH), OCH₂), 1.79 (m, 4 H, OCH₂CH₂), 1.45 (m, 4 H, OCH₂CH₂CH₂),

110.8 (2 C, ArCH), 80.7 (2 C, CϵCH), 80.3 (2 C, CϵCH), 68.8 (2 1.28–1.39 (m, 12 H, CH₂), 1.28 [18, H C(CH₃)₃], 0.21 [s, 18 H,

C, OCH₂), 34.0 [2 C, C(CH₃)₃], 31.3 [6 C, C(CH₃)₃], 29.6 (4 C, Si(CH₃)₃] ppm. ¹³C NMR (100.5 MHz, CDCl₃, 25 °C): δ = 159.1

CH₂), 29.5 (2 C, CH₂), 29.3 (2 C, CH₂), 29.1 (2 C, CH₂), 25.9 (2 (2 C, ArC), 143.0 (2 C, ArC), 131.6 (2 C, ArCH), 127.7 (2 C,

C, CH ) ppm. IR (KBr): ν = 3315, 3288, 2926, 2855, 1603, 1500, ArCH), 111.7 (2 C, ArCH), 110.3 (2 C, ArC), 90.4 (2 C,

˜

2

1468, 1393, 1363, 1270, 1140, 1105, 1021, 894, 813, 635 cm^–1. UV/

SiCϵCCϵC), 88.4 (2 C, SiCϵCCϵC), 77.2 (2 C, SiCϵC), 74.3 (2

Vis (CH₂Cl₂): λ_max= 242, 250, 298, 306 nm. MS (FAB): m/z = 543 C, SiCϵC), 69.0 (2 C, OCH₂), 34.0 [2 C, C(CH₃)₃], 31.3 [6 C,

[M⁺]. C₃₈H₅₄O₂(542.81): calcd. C 84.08, H 10.03; found 83.91, H

9.89.

C(CH₃)₃], 29.9–26.3 (10 C, CH₂), –0.34 [6 C, Si(CH₃)₃] ppm. IR

(KBr): ν = 2961, 2927, 2855, 2204, 2099, 1729, 1601, 1519, 1499,

˜

1466, 1391, 1364, 1283, 1250, 1157, 1075, 1041, 846, 815, 762, 735,

669 cm^–1. UV/Vis (CH₂Cl₂): λ_max= 288, 317, 328 nm. MS (FAB):

m/z = 707 [M⁺]. C₄₆H₆₆O₂Si₂(707.17): calcd. C 78.13, H 9.41;

found C 77.83, H 9.21.

1,16-Bis(4-tert-butyl-2-ethynylphenyloxy)hexadecane (10c): To a

solution of diisopropylamine (2.58 g, 25.56 mmol) in THF (64 mL)

a 1.6  solution of n-butyllithium (6 mL, 25.60 mmol) in hexane

was added at 0 °C. From the resulting 0.31  LDA solution, 50 mL

(15.50 mmol) were added to a solution of 5c (1.84 g, 2.07 mmol) in

THF (50 mL). By TLC monitoring (TLC: ethyl acetate/hexane, 1:9,

R_f= 0.45) it was demonstrated that the reaction was completed

after 30 min. The reaction mixture was worked up with aqueous

HCL solution (10%, 150 mL) and CH₂Cl₂(150 mL). After separat-

ing the two layers, the aqueous layer was extracted three times with

CH₂Cl₂(100 mL each), and the combined organic phases washed

with water (250 mL). Drying of the CH₂Cl₂solution with Na₂SO₄

and subsequent column chromatography (silica gel, ethyl acetate/

hexane, 1:9) gave 10c as a white solid (1.00 g, 85 %). ¹H NMR

1,14-Di{4-tert-butyl-2-[4-(trimethylsilyl)butadiynyl]phenyloxy}-

tetradecane (12b): A filtered solution of CuCl (11.14 g, 11.52 mmol)

in acetone (80 mL) and TMEDA (545 mg, 4.70 mmol) was added

dropwise to a solution of 10b (0.70 g, 1.29 mmol) and 11 (1.38 g,

14.08 mmol) as for the synthesis of 12a (TLC control: CH₂Cl₂/hex-

ane, 3:7, R_f= 0.49). After 18 h additionally 50 mL of the Cu/

TMEDA solution and (trimethylsilyl)acetylene (11, 1.38 g,

14.08 mmol) were added. After a total of 24 h an aqueous solution

of HCl (10%, 10 mL), water (60 mL) and hexane (100 mL) was

added to the mixture. Extraction and washings with hexane (3 ×

(400 MHz, CDCl₃, 25 °C): δ = 7.44 (d, ⁴J = 2.6 Hz, 2 H, ArH), 100 mL), aqueous HCl (10%, 70 mL) and drying was performed

7.27 (dd, ³J = 8.7 Hz, ⁴J = 2.6 Hz, 2 H, ArH), 6.78 (d, ³J = 8.7 Hz,

like with 12a. By column chromatography a yellow solid 12b was

1

2 H, ArH), 3.99 (t, ³J = 6.6 Hz, 4 H, OCH₂), 3.22 (s, 2 H, CϵCH), obtained (568 mg, 60%). H NMR (400 MHz, CDCl₃, 25 °C): δ =

1.80 (m, 4 H, OCH₂CH₂), 1.44 (m, 4 H, OCH₂CH₂CH₂), 1.32– 7.43 (d, ⁴J = 2.6 Hz, 2 H, ArH), 7.27 (dd, ³J = 8.7 Hz, ⁴J = 2.6 Hz,

3

1.24 (m, 20 H, CH₂), 1.26 [s, 18 H, C(CH₃)₃] ppm. ¹³C NMR

2 H, ArH), 6.75 (d, J = 8.8 Hz, 2 H, ArH), 3.97 (t, J = 6.6 Hz,

(100.5 MHz, CDCl₃, 25 °C): δ = 158.0 (2 C, ArC), 143.0 (2 C, 4 H, OCH₂), 1 . 7 9 ( m, 4 H , O CH₂CH₂), 1. 44 (m, 4 H,

ArC), 131.0 (2 C, ArCH), 127.1 (2 C, ArC), 111.7 (2 C, ArCH), OCH₂CH₂CH₂), 1.33–1.25 (m, 16 H, CH₂), 1.24 [s, 18 H, C(CH₃)₃],

110.9 (2 C, ArCH), 80.7 (2 C, CϵCH), 80.3 (2 C, CϵCH), 68.9 (2 0.20 [s, 18 H, Si(CH₃)₃] ppm. ¹³C NMR (100.5 MHz, CDCl₃,

C, OCH₂), 34.0 [2 C, C(CH₃)₃], 31.3 [6 C, C(CH₃)₃], 29.7 (6 C, 25 °C): δ = 159.1 (2 C, ArC), 143.1 (2 C, ArC), 131.6 (2 C, ArCH),

CH₂), 29.6 (2 C, CH₂), 29.3 (2 C, CH₂), 29.1 (2 C, CH₂), 25.9 (2 127.8 (2 C, ArCH), 111.7 (2 C, ArCH), 110.3 (2 C, ArC), 90.4 (2

Eur. J. Org. Chem. 2006, 1508–1524

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1517

C. Klinger, O. Vostrowsky, A. Hirsch

FULL PAPER

C, SiCϵCCϵC), 88.4 (2 C, SiCϵCCϵC), 77.2 (2 C, SiCϵC), 74.3

1,16-Bis(2-butadiynyl-4-tert-butylphenyloxy)hexadecane (14c): To a

(2 C, SiCϵC), 69.0 (2 C, OCH₂), 34.0 [2 C, C(CH₃)₃], 31.3 [6 C, solution of 12c (567 mg, 0.74 mmol) in a 1:1 mixture of CH₃OH/

C(CH₃)₃], 29.7 (2 C, CH₂), 29.6 (2 C, CH₂), 29.5 (2 C, CH₂), 29.4 THF (10 mL) a spatulum tip of K₂CO₃was added and the mixture

(2 C, CH₂), 29.1 (2 C, CH₂), 25.9 (2 C, CH₂), –0.6 [6 C, Si(CH₃)₃]

stirred. After 1 h stirring no more starting material was observed

(TLC control: ethyl acetate/hexane, 2:8, R_f= 0.52). Subsequently,

aqueous HCl (10%, 70 mL), water (45 mL) and hexane (140 mL)

ppm. IR (KBr): ν = 2961, 2925, 2853, 2203, 2099, 1601, 1499, 1466,

˜

1392, 1364, 1284, 1250, 1156, 1040, 846, 816, 762, 636 cm^–1. UV/

Vis (CH₂Cl₂): λ_max= 256, 271, 288, 316, 328 nm. MS (FAB): m/z = were added and the layers separated. The aqueous layer was ex-

735 [M⁺]. C₄₈H₇₀O₂Si₂(735.22): calcd. C 78.41, H 9.60; found C

77.91, H 9.74.

tracted twice with hexane (140 mL each) and the combined organic

phases dried with Na₂SO₄. The hexane solution was concentrated

and immediately used without characterization.

1,16-Bis[4-tert-butyl-2-(4-trimethylsilylbutadiynyl)phenyloxy]hexa-

decane (12c): CuCl (1.86 g, 18.80 mmol) and TMEDA (0.87 g,

7.52 mmol) were dissolved in acetone (150 mL) and the solution

stirred for 1 h. Subsequently, the mixture was filtered and washed

with acetone as for 12a. This solution was slowly added to a solu-

tion of 10c (1.09 g, 2.01 mmol) and 11 (2.15 g, 22.00 mmol) in ace-

tone (90 mL). Oxygen was passed through the reaction mixture and

the reaction progress monitored by TLC (CH₂Cl₂/hexane, 4:6, R_f

= 0.69). During the following 24 h, additional four portions

(2 × 0.59 g, 6.02 mmol each and 2 × 0.28 g, 2.85 mmol each) of

11 were added. Work up was performed with aqueous HCl (10%,

140 mL), water (140 mL), hexane (200 mL), two extractions with

hexane (150 mL each), washings with HCl (10%, 200 mL) and

water (2 × 250 mL) and drying (Na₂SO₄) as for compound 12a.

Column chromatography (silica gel, CH₂Cl₂/hexane, 2:8) yielded

616 mg (40%) of a white solid 12c. ¹H NMR (400 MHz, CDCl₃,

Dibenzo-dioxacycloalkanetetrayne Derivative 15a: TMEDA

(455 mg, 3.92 mmol) was added to a solution of CuCl (958 mg,

9.68 mmol) in acetone (50 mL) and the mixture stirred for 1 h. Sub-

sequently, the reaction mixture was filtered several times. The hex-

ane solution of 14a, described above, was diluted with acetone

(250 mL), and added dropwise to the filtrate, while a gentle stream

of oxygen was passed through the solution. After a period of 15 h

no more starting material was observed by TLC control (CH₂Cl₂/

hexane, 2:8, R_f= 0.42), and aqueous HCl (10%, 50 mL), water

(50 mL) and hexane (200 mL) were added. After separating the two

layers, the aqueous layer was extracted twice with hexane (200 mL

each) and the combined organic phases dried with Na₂SO₄. By

column chromatography (silica gel, CH₂Cl₂/hexane, 2:8) the yellow

product zone was separated and 15a was isolated as a yellow oil

(42 mg, 7 % with respect to 12a). ¹H NMR (400 MHz, CDCl₃,

4

3

4

25 °C): δ = 7.43 (d, J = 2.5 Hz, 2 H, ArH), 7.27 (dd, J = 8.7 Hz,

22 °C): δ = 7.42 (d, J = 2.2 Hz, 2 H, ArH), 7.32 (dd, J = 2.2 Hz,

3

⁴J = 2.5 Hz, 2 H, ArH), 6.75 (d, J = 8.7 Hz, 2 H, ArH), 3.97 (t,

3

³J = 8.6 Hz, 2 H, ArH), 6.78 (d, J = 8.6 Hz, ArH), 3.99 (t, J =

5.5 Hz, 4 H, OCH₂), 1.74 (m, 4 H, OCH₂CH₂), 1.56 (m, 4 H,

OCH₂CH₂CH₂), 1.40–1.30 (m, 12 H, CH₂), 1.25 [s, 18 H, C–(CH₃)₃]

ppm. ¹³C NMR (100.50 MHz, CDCl₃, 25 °C): δ = 160.8 (2 C,

ArC), 143.5 (2 C, ArC), 130.7 (2 C, ArCH), 128.5 (2 C, ArCH),

112.3 (2 C, ArCH), 110.1 (2 C, ArC), 77.6 [2 C, (ArCϵCCϵC)₂],

75.1 [2 C, (ArCϵCCϵC)₂], 69.7 (2 C, OCH₂), 67.6 [2 C,

(ArCϵCCϵC)₂], 64.0 (ArCϵCCϵC)₂) , 34.1 [2 C, C(CH₃)₃], 31.3

[6 C, C(CH₃)₃], 30.3 (2 C, CH₂), 30.2 (2 C, CH₂), 30.1 (2 C, CH₂),

29.7 (2 C, CH₂), 26.9 (2 C, CH₂) ppm. IR (NaCl): ν˜ = 2963, 2922,

2853, 2152, 2048, 1599, 1499, 1466, 1386, 1362 1261, 1093, 1024,

805, 705, 624 cm^–1. UV/Vis (CH₂Cl₂): λ_max= 286, 335, 356, 384,

416 nm. MS (FAB): m/z = 560 [M⁺]. C₄₀H₄₈O₂(560.78): calcd. C

85.67, H 8.63; found C 85.24, H 8.56.

³J = 6.7 Hz, 4 H, OCH₂), 1.79 (m, 4 H, OCH₂CH₂), 1.44 (m, 4 H,

OCH₂CH₂CH₂), 1.33–1.24 (m, 20 H, CH₂), 1.24 [s, 18 H, C(CH₃)₃],

0.20 [s, 18 H, Si(CH₃)₃] ppm. ¹³C NMR (100.5 MHz, CDCl₃,

25 °C): δ = 159.1 (2 C, ArC), 143.1 (2 C, ArC), 131.6 (2 C, ArCH),

127.8 (2 C, ArCH), 111.7 (2 C, ArCH), 110.3 (2 C, ArC), 90.4 (2

C, SiCϵCCϵC), 88.4 (2 C, SiCϵCCϵC), 77.2 (2 C, SiCϵC), 74.3

(2 C, SiCϵC), 69.0 (2 C, OCH₂), 34.0 [2 C, C(CH₃)₃], 31.3 [6 C,

C(CH₃)₃], 29.7 (6 C, CH₂), 29.6 (2 C, CH₂), 29.3 (2 C, CH₂), 29.1

(2 C, CH₂), 25.9 (2 C, CH₂), –0.3 [6 C, Si(CH₃)₃] ppm. IR (KBr):

ν = 2961, 2926, 2852, 2204, 2099, 1601, 1499, 1467, 1391, 1364,

˜

1284, 1250, 1157, 1039, 847, 815, 761, 636 cm^–1. UV/Vis (CH₂Cl₂):

λ_max= 256, 271, 288, 316, 328 nm. MS (FAB): m/z = 764 [M⁺].

C₅₀H₇₄O₂Si₂(763.27): calcd. C 78.67, H 9.77; found C 77.98, H

9.55.

Dibenzo-dioxacycloalkanetetrayne Derivative 15b: CuCl (400 mg,

4.00 mmol) and TMEDA (192 mg, 1.66 mmol) were dissolved in

acetone (25 mL) and stirred for 1 h. Subsequently, the solution was

filtered several times and the filter cake was rinsed each time with

3–4 mL of acetone. To this dark green solution the hexane solution

of 14b (see above), diluted with acetone (55 mL), was added drop-

wise over a period of 3 h. During this time, a gentle stream of

oxygen was passed through the mixture. After the completion of

the reaction (TLC control: ethyl acetate/hexane, 2:8; R_f= 0.63)

water (20 mL), aqueous HCl (10%, 20 mL) and hexane (60 mL)

were added and the layers separated. The aqueous layer was ex-

tracted twice with hexane (50 mL each), the combined organic lay-

ers were washed with water (200 mL) and dried with Na₂SO₄.

Colum chromatography allowed the isolation of the yellow product

zone, and 15b was isolated as a yellow oil (11 mg, 8% relative to

12b). ¹H NMR (400 MHz, CDCl₃, 25 °C): δ = 7.45 (d, ⁴J = 2.6 Hz,

1,12-Bis(2-butadiynyl-4-tert-butylphenyloxy)dodecane (14a): A spat-

ulum tip of K₂CO₃was added to TMS-protected 12a (750 mg,

1.06 mmol), dissolved in a 1:1 mixture of wet CH₃OH and THF.

After 10 min no more starting material was observed (TLC:

CH₂Cl₂/hexane, 2:8, R_f= 0.30), and subsequently water (50 mL),

aqueous HCl (10%, 30 mL) and hexane (100 mL) were added. The

reaction mixture was extracted with hexane twice (70 mL each) and

the combined organic layers dried with Na₂SO₄. The remaining

solution was concentrated to a few mL and immediately trans-

formed to the tetrayne 15a. MS (FAB): m/z = 563 [M⁺].

1,14-Bis(2-butadiynyl-4-tert-butylphenyloxy)tetradecane (14b): To a

solution of the TMS-protected butadiynyl derivative 12b (180 mg,

0.24 mmol) in wet CH₃OH (3 mL) and THF (4 mL) a minute

amount of K₂CO₃was added. By means of TLC monitoring

(CH₂Cl₂/hexane, 3:7, R_f= 0.38), after 1 h no more starting material

was detected. Then aqueous HCl (10%, 15 mL), water (15 mL) and

hexane (45 mL) were added. The layers were separated and the

aqueous layer was extracted twice with hexane (50 mL each). The

combined hexane layers were dried with Na₂SO₄. The clear and

colorless solution obtained was carefully concentrated to 10 mL

and immediately applied for the subsequent transformation. MS

(FAB): m/z = 591 [M⁺].

3

2 H, ArH), 7.31 (dd, ⁴J = 2.5 Hz, J = 8.7 Hz, 2 H, ArH), 6.76 (d,

3

³J = 8.8 Hz, ArH), 3.99 (t, J = 5.4 Hz, 4 H, OCH₂), 1.75 (m, 4 H,

OCH₂CH₂), 1.53 (m, 4 H, OCH₂CH₂CH₂), 1.40–1.30 (m, 20 H,

CH₂), 1.25 [s, 18 H, C–(CH₃)₃] ppm. ¹³C NMR (100.50 MHz,

CDCl₃, 25 °C): δ = 160.0 (2 C, ArC), 143.2 (2 C, ArC), 131.8 (2 C,

ArCH), 128.5 (2 C, ArCH), 111.5 (2 C, ArCH), 109.5 (2 C, ArC),

77.6 [2 C, (ArCϵCCϵC)₂], 75.2 [2 C, (ArCϵCCϵC)₂], 69.1 (2 C,

1518

www.eurjoc.org

Eur. J. Org. Chem. 2006, 1508–1524

Synthesis of Alkylene-Bridged Diphenyl-Oligoynes

FULL PAPER

OCH₂), 67.7 [2 C, (ArCϵCCϵC)₂], 64.2 (ArCϵCCϵC)₂) , 34.1 [2 ArCH), 88.9 (2 C, Br₂C=CH), 68.5 (2 C, OCH₂), 34.2 [2 C, C(CH₃)₃],

C, C(CH₃)₃], 31.3 [6 C, C(CH₃)₃], 29.7 (2 C, CH₂), 29.4 (2 C, CH₂), 31.4 [6 C, C(CH₃)₃], 29.7 (10 C, CH₂), 29.6 (2 C, CH₂), 29.3 (2 C,

29.3 (2 C, CH₂), 29.2 (2 C, CH₂), 29.1 (2 C, CH₂), 29.0 (2 C, CH₂), CH ), 29.2 (2 C, CH ), 26.1 (2 C, CH ) ppm. IR (KBr): ν = 2959,

˜

2

26.3 (2 C, CH ) ppm. IR (NaCl): ν = 2963, 2922, 2852, 2151, 2047,

2922, 2850, 1606, 1494, 1467, 1391, 1363, 1305, 1251, 1138, 1106,

˜

2

1598, 1498, 1466, 1387, 1363, 1261, 1096, 1022, 804, 704, 625 cm^–1. 1018, 939, 901, 845, 812, 736, 673, 631, 581, 497 cm^–1. UV/Vis

UV/Vis (CH₂Cl₂): λ_max= 286, 335, 355, 383, 415 nm. MS (FAB): (CH₂Cl₂): λ_max= 259, 307 nm. MS (FAB): m/z = 946 [M⁺].

m/z = 588 [M⁺]. C₄₂H₅₂O₂(588.83): calcd. C 85.66, H 8.90; found

C₄₄H₆₆Br₄O₂(946.63): calcd. C 55.83, H 7.03; found C 56.28, H

7.37.

C 84.97, H 8.88.

Dibenzo-dioxacycloalkanetetrayne Derivative 15c: CuCl (1.41 g,

14.20 mmol) and TMEDA (0.68 g, 5.90 mmol) in acetone (90 mL)

was stirred for 1 h and subsequently filtered repeatedly until no

precipitation occurred anymore. The filter cake was rinsed with

acetone (5 mL each) for each filtration cycle. Subsequently, the

readily prepared hexane solution of 14c (see above), diluted with

acetone (200 mL), was added dropwise to this solution over a

period of 2 h. During this period of time, a gentle stream of oxygen

was bubbled through the solution. After 20 h by TLC control no

more starting material was observed and a yellow product band

occurred (TLC: ethyl acetate/hexane, 1:9; R_f= 0.66). Water

(60 mL), aqueous HCl (10%, 60 mL) and hexane (150 mL) were

added to the reaction mixture and the layers separated. The aque-

ous layer was extracted twice with hexane (160 mL each) and the

combined organic layers washed with aqueous HCl (10%, 100 mL)

and water (200 mL), and dried with Na₂SO₄. By column

chromatography (silica gel, ethyl acetate/hexane, 3:97) 15c was iso-

lated as a yellow oil (6 mg, 1.3%). ¹H NMR (400 MHz, CDCl₃,

1,32-Bis[4-tert-butyl-2-(2,2-dibromoethenyl)phenyloxy]dotriacontane

(9e): To a solution of CBr₄(10.46 g, 31.51 mmol) in CH₂Cl₂

(65 mL) at 0 °C PPh₃(16.51 g, 63.01 mmol) was added. To this

yellowish suspension a solution of 8e (5.50 g, 6.85 mmol) in

CH₂Cl₂(100 mL) was added dropwise and subsequently stirred for

30 min at 0 °C and for 30 min at room temperature. Subsequently,

CH₂Cl₂(300 mL) and water (300 mL) were added and the two lay-

ers separated. The organic layer was washed twice with water

(300 mL each) and dried with Na₂SO₄. By column chromatography

(silica gel 60, CH₂Cl₂/hexane, 1:1) the product 9e was obtained as

1

a white solid (7.38 g, 96.6%). H NMR (400 MHz, CDCl₃, 25 °C):

4

δ = 7.74 (d, J = 2.3 Hz, 2 H, ArH), 7.60 (s, 2 H, CHCBr₂), 7.27

4

3

(dd, J = 2.3 Hz, J = 8.7 Hz, 2 H, ArH), 6.76 (d, J = 8.7 Hz, 2

H, ArH), 3.92 (t, ³J = 6.4 Hz, 4 H, OCH₂), 1.78 (m, 4 H,

OCH₂CH₂), 1.40 (m, 4 H, OCH₂CH₂CH₂), 1.29 [s, 18 H, C(CH₃)

₃], 1.24 (br. s, 52 H, CH₂) ppm. ¹³C NMR (100.5 MHz, CDCl₃,

25 °C): δ = 153.8 (2 C, ArC), 142.4 (2 C, ArC), 133.2 (2 C, ArCH),

126.3 (2 C, ArCH), 123.7 (4 C, ArCH and Br₂C=CH), 111.0 (2 C,

ArCH), 88.9 (2 C, Br₂C=CH), 68.6 (2 C, OCH₂), 34.3 [2 C, C(CH₃)₃],

31.5 [6 C, C(CH₃)₃], 29.8 (22 C, CH₂), 29.7 (2 C, CH₂), 29.5 (2 C,

4

22 °C): δ = 7.46 (d, J = 2.4 Hz, 2 H, ArH), 7.31 (dd, J = 2.6 Hz,

3

³J = 8.8 Hz, 2 H, ArH), 6.75 (d, J = 8.8 Hz, ArH), 3.98 (t, J =

5.7 Hz, 4 H, OCH₂), 1.77 (m, 4 H, OCH₂CH₂), 1.49 (m, 4 H,

OCH₂CH₂CH₂), 1.38–1.23 (m, 16 H, CH₂), 1.25 [s, 18 H, C–(CH₃)₃]

ppm. ¹³C NMR (100.50 MHz, CD₂Cl₂, 22 °C): δ = 160.0 (2 C,

CH ), 29.3 (2 C, CH ), 26.2 (2 C, CH ) ppm. IR (KBr): ν = 2916,

˜

2

2851, 1604, 1494, 1473, 1390, 1363, 1306, 1254, 1130, 1105, 1019,

939, 903, 844, 804, 717 cm^–1. UV/Vis (CH₂Cl₂): λ_max= 259,

ArC), 143.2 (2 C, ArC), 131.8 (2 C, ArCH), 128.5 (2 C, ArCH), 307 nm. MS (FAB): m/z = 1114 [M⁺]. C₅₆H₉₀Br₄O₂(1114.94):

111.5 (2 C, ArCH), 109.5 (2 C, ArC), 77.6 [2 C, (ArCϵCCϵC)₂],

75.2 [2 C, (ArCϵCCϵC)₂], 69.1 (2 C, OCH₂), 67.6 [2 C,

(ArCϵCCϵC)₂], 64.2 (ArCϵCCϵC)₂) , 34.1 [2 C, C(CH₃)₃], 31.3

[6 C, C(CH₃)₃], 29.7 (2 C, CH₂), 29.4 (2 C, CH₂), 29.3 (2 C, CH₂),

29.2 (2 C, CH₂), 29.1 (2 C, CH₂), 28.7 (2 C, CH₂), 26.3 (2 C,

calcd. C 60.33, H 8.14; found C 60.28, 8.15.

1,40-Bis[4-tert-butyl-2-(2,2-dibromoethenyl)phenyloxy]tetracontane

(9f): PPh₃(11.99 g, 45.78 mmol) was added to a solution of CBr₄

(7.60, 22.89 mmol) in CH₂Cl₂(40 mL) at 0 °C. To the resulting

yellow suspension the bis(aldehyde) 8f (4.37 g, 4.78 mmol), dis-

solved in CH₂Cl₂(180 mL), was added dropwise within 20 min.

Subsequently, the cooling bath was removed and the progress of

the reaction monitored by TLC (CH₂Cl₂/hexane, 2:8, R_f= 0.50).

After 1 h, CH₂Cl₂(300 mL) and water (300 mL) were added and

the layers separated. The aqueous layer was extracted with CH₂Cl₂

(200 mL) and the combined organic layers washed twice with water

(300 mL each). By column chromatography (silica gel, CH₂Cl₂/hex-

ane, 2:8) the product 9f was isolated (5.68 g, 97%) as a white solid.

¹H NMR (400 MHz, CDCl₃, 25 °C): δ = 7.74 (d, ⁴J = 2.3 Hz, 2 H,

CH ) ppm. IR (NaCl): ν = 2925, 2854, 2196, 2126, 2073, 1737,

˜

2

1600, 1499, 1466, 1363, 1263, 1150, 1133, 1101, 891, 813, 720,

626 cm^–1. UV/Vis (CH₂Cl₂): λ_max= 271, 286, 336, 357, 384, 416

nm. MS (FAB): m/z = 617 [M⁺]. C₄₄H₅₆O₂(616.89): calcd. C 85.66,

H 9.15; found C 84.89, H 9.01.

Synthesis of Hexayne Macrocycles 18a–c

1,20-Bis[4-tert-butyl-2-(2,2-dibromoethenyl)phenyloxy]eicosane (9d):

A solution of CBr₄(7.23 g, 21.78 mmol) in CH₂Cl₂(40 mL) was

cooled to 0 °C and PPh₃(11.41 g, 43.55 mmol) was added. To the

resulting yellow suspension the bis(aldehyde) 8d (3.00 g,

4.73 mmol), dissolved in CH₂Cl₂(50 mL) was added and the cool-

ing bath removed. After 30 min, when TLC control (CH₂Cl₂, R_f=

0.82) showed complete transformation, water (400 mL) and

CH₂Cl₂(300 mL) were added. After separating the layers, the aque-

ous layer was extracted twice with CH₂Cl₂(200 mL each). The

combined organic layers were dried with Na₂SO₄. From column

chromatography (silica gel, CH₂Cl₂), the pure product 9d was ob-

4

3

ArH), 7.61 (s, 2 H, CHCBr₂), 7.27 (dd, J = 2.3 Hz, J = 8.7 Hz,

3

2 H, ArH), 6.76 (d, J = 8.7 Hz, 2 H, ArH), 3.93 (t, J = 6.4 Hz,

4 H, OCH₂), 1 . 7 7 ( m, 4 H , O CH₂CH₂), 1. 42 (m, 4 H,

OCH₂CH₂CH₂), 1.29 [s, 18 H, C(CH₃)₃], 1.24 (br. s, 68 H,

CH₂) ppm. ¹³C NMR (100.5 MHz, CDCl₃, 25 °C): δ = 153.9 (2 C,

ArC), 142.6 (2 C, ArC), 133.4 (2 C, ArCH), 126.4 (4 C, ArCH

and Br₂C=CH), 123.8 (2 C, ArC), 111.0 (2 C, ArCH), 88.9 (2 C,

Br₂C=CH), 68.5 (2 C, OCH₂), 34.2 [2 C, C(CH₃)₃], 31.4 [6 C,

C(CH₃)₃], 29.7 (30 C, CH₂), 29.5 (2 C, CH₂), 29.3 (2 C, CH₂), 29.1

1

tained as a white solid (4.37 g, 98%). H NMR (400 MHz, CDCl₃,

(2 C, CH ), 26.1 (2 C, CH ) ppm. IR (KBr): ν = 2916, 2851, 1604,

˜

2

25 °C): δ = 7.75 (d, ⁴J = 2.4 Hz, 2 H, ArH), 7.61 (s, 2 H, CHCBr₂),

7.28 (dd, ⁴J = 2.4 Hz, ³J = 8.5 Hz, 2 H, ArH), 6.76 (d, ³J = 8.7 Hz,

2 H, ArH), 3.93 (t, ³J = 6.5 Hz, 4 H, OCH₂), 1.77 (m, 4 H,

OCH₂CH₂), 1.42 (m, 4 H, OCH₂CH₂CH₂), 1.29 (br. s, 28 H, CH₂),

1.25 [s, 18 H, C(CH₃)₃] ppm. ¹³C NMR (100.5 MHz, CDCl₃,

1494, 1473, 1390, 1363, 1306, 1254, 1130, 1105, 1019, 939, 903,

844, 804, 717 cm^–1UV/Vis (CH₂Cl₂): λ_max= 259, 307 nm. MS

.

(FAB): m/z = 1227 [M⁺]. C₆₄H₁₀₆Br₄O₂(1227.15): calcd. C 62.64,

H 8.71; found C 62.71 H: 8.70.

25 °C): δ = 153.9 (2 C, ArC), 142.6 (2 C, ArC), 133.4 (2 C, ArCH), 1,20-Bis(4-tert-butyl-2-ethynylphenyloxy)eicosane (10d): Diisopro-

126.4 (4 C, ArCH and Br₂C=CH), 123.8 (2 C, ArC), 111.0 (2 C, pylamine(2.626.37 mmol) and a 1.6  solution of n-butyllithium

Eur. J. Org. Chem. 2006, 1508–1524

www.eurjoc.org

1519

C. Klinger, O. Vostrowsky, A. Hirsch

FULL PAPER

(16.54 mL, 26.46 mmol) in hexane were mixed and transferred into

THF (66 mL) and stirred for 1 h. The resulting 0.3  lithium diiso-

propylamide solution was given in a dropping funnel, and a few

drops of the solution were added to a suspension of the tetrabromo

compound 9d (2.00 g, 2.11 mmol) in THF (30 mL) at –50 °C. When

the suspended solid 9d dissolved, the mixture was cooled to –80 °C

and 28 mL of the LDA solution were added. The reaction process

was monitored by TLC (CH₂Cl₂/hexane, 2:8, R_f= 0.09). After

20 min each, 8 mL (2.40 mmol) and two times 10 mL (3.00 mmol)

of the LDA solution from above were added additionally to obtain

a complete transformation. After allowing to warm to room tem-

perature, an aqueous HCl solution (10%, 200 mL) and CH₂Cl₂

(14 mL, 22.40 mmol) in hexane and stirred for 1 h. In the mean-

time, the tetrabromo compound 9f (1.58 g, 1.29 mmol) was dis-

solved in THF (50 mL) and cooled to –20 °C (partially precipitat-

ing). To this resulting suspension 26 mL (7.95 mmol) of the 0.3 

LDA solution from above were added dropwise, and the solution

warmed to room temperature over a period of 2 h. At a tempera-

ture of 10 °C the former white suspension became reddish and dark

while turning clear. TLC control (CH₂Cl₂/hexane, 2:8, R_f= 0.23)

proved complete conversion. Water (60 mL), aqueous HCl (10%,

150 mL) and CH₂Cl₂(200 mL) were added and the two layers

formed were separated. The aqueous layer was extracted twice with

CH₂Cl₂(200 mL each), and the combined organic layers were

(200 mL) were added. The two phases were separated, and the washed with water and dried with Na₂SO₄. By means of column

aqueous layer extracted three times with CH₂Cl₂(150 mL each).

The combined organic layers were dried with Na₂SO₄and by me-

ans of column chromatography (silica gel, CH₂Cl₂/hexane, 1:3) the

product 10d was obtained as a white solid (988 mg, 75%). ¹H NMR

chromatography (silica gel, CH₂Cl₂/hexane, 2:8) product 10f was

isolated (723 mg, 62 %) as a white solid. ¹H NMR (400 MHz,

4

CDCl₃, 25 °C): δ = 7.44 (d, J = 2.6 Hz, 2 H, ArH), 7.28 (dd, J =

3

2.6 Hz, J = 8.7 Hz, 2 H, ArH), 6.78 (d, J = 8.8 Hz, 2 H, ArH),

(400 MHz, CDCl₃, 25 °C): δ = 7.45 (d, ⁴J = 2.6 Hz, 2 H, ArH), 3.99 (t, J = 6.7 Hz, 4 H, OCH₂), 3.22 (s, 2 H, ArCϵC–H), 1.80

3

7.28 (dd, ⁴J = 2.6 Hz, ³J = 8.7 Hz, 2 H, ArH), 6.78 (d, ³J = 8.8 Hz,

2 H, ArH), 3.99 (t, ³J = 6.6 Hz, 4 H, OCH₂), 3.22 (s, 2 H, ArCϵC–

(m, 4 H, OCH₂CH₂), 1.44 (m, 4 H, OCH₂CH₂CH₂), 1.27 [s, 18 H,

C(CH₃)₃], 1.24 (br. s, 68 H, CH₂) ppm. ¹³C NMR (100.5 MHz,

H), 1.80 (m, 4 H, OCH₂CH₂), 1.45 (m, 4 H, OCH₂CH₂CH₂), 1.27 CDCl₃, 25 °C): δ = 158.0 (2 C, ArC), 142.9 (2 C, ArC), 131.0 (2 C,

(s, 28 H, CH₂), 1.24 [s, 18 H, C(CH₃)₃] ppm. ^{1 3}C NMR ArCH), 127.1 (2 C, ArCH), 111.6 (2 C, ArCH), 110.9 (2 C,

(100.5 MHz, CDCl₃, 25 °C): δ = 158.0 (2 C, ArC), 143.0 (2 C, ArCCϵC), 80.7 (2 C, ArCϵC), 80.3 (2 C, ArCϵC), 68.8 (2 C,

ArC), 131.0 (2 C, ArCH), 127.1 (2 C, ArCH), 111.7 (2 C, ArCH), OCH₂), 34.0 [2 C, C(CH₃)₃], 31.3 [6 C, C(CH₃)₃], 29.7 (30 C, CH₂),

110.9 (2 C, ArCCϵC), 80.7 (2 C, ArCϵC), 80.3 (2 C, ArCϵC), 29.6 (2 C, CH₂), 29.3 (2 C, CH₂), 29.1 (2 C, CH₂), 25.9 (2 C,

68.9 (2 C, OCH₂), 34.0 [2 C, C(CH₃)₃], 31.3 (10 C, CH₂), 29.7 [6 CH ) ppm. IR (KBr): ν = 3443, 3310, 3286, 2921, 2849, 2361, 1636,

˜

2

C, C(CH₃)₃], 29.6 (2 C, CH₂), 29.4 (2 C, CH₂), 29.1 (2 C, CH₂), 1502, 1463, 1391, 1269, 1141, 1104, 819, 725, 635 cm^–1. UV/Vis

25.9 (2 C, CH ) ppm. IR (KBr): ν = 3310, 3284, 2921, 2849, 2106,

(CH₂Cl₂): λ_max= 241, 249, 298,305 nm. C₆₄H₁₀₆O₂(907.49): calcd.

˜

2

1603, 1503, 1463, 1391, 1362, 1271, 1255, 1141, 1105, 1004, 891,

819, 725, 649, 635, 605 cm^–1. UV/Vis (CH₂Cl₂): λ_max= 242, 250,

298, 306 nm. MS (FAB): m/z = 628 [M⁺]. C₄₄H₆₆O₂(626.97): calcd.

C 84.29, H 10.61; found C 83.98, H 10.57.

C 84.70, H 11.77; found C 84.33, H 11.85.

1,20-Bis[4-tert-butyl-2-(6-trimethylsilylhexa-1,3,5-triynyl)phenyl-

oxy]eicosane (17a): The ethynyl derivative 10d (300 mg, 0.48 mmol)

was dissolved in dry and degassed THF (11 mL) at 0 °C. Sub-

sequently the solution was treated with a 1.6  solution of n-butyl-

lithium (62 mL, 0.99 mmol) in hexane. After 60 min, CuCl (98 mg,

0.99 mmol) was added, and the mixture was warmed to room tem-

perature. The resulting solution was diluted with pyridine (7 mL)

and cooled again to 0 °C. Subsequently, a solution of 1-bromo-4-

(trimethylsilyl)buta-1,3-diyne (16, 279 mg, 1.39 mmol) in THF

(7 mL) was added and the heterocoupling reaction process con-

trolled by TLC (CH₂Cl₂/hexane, 2:8, R_f= 0.32). After 20 min, an-

other addition of 16 (undiluted, 106 mg, 0.52 mmol) followed. Af-

ter a total of 60 min, aqueous HCl (10%, 40 mL), water (40 mL)

and hexane (60 mL) were added. The two layers were separated,

and the aqueous layer was extracted three times with hexane

(60 mL each). The combined organic layers were dried with

Na₂SO₄and the product 17a was isolated by column chromatog-

raphy (silica gel, CH₂Cl₂/hexane, 2:8) as a white-yellowish solid

1,32-Bis(4-tert-butyl-2-ethynylphenyloxy)dotriacontane (10e): To a

solution of diisopropylamine (8.48 g, 84.01 mmol) in THF

(210 mL) a solution of n-butyllithium in hexane (1.6 , 52.5 mL,

84.01 mmol) was added at 0 °C and stirred for 1 h at this tempera-

ture. Under vigorous stirring, 140 mL of this LDA solution

(42 mmol) were added rapidly dropwise to a solution of 9e (7.38 g,

6.62 mmol) in THF (110 mL) at –80 °C. Than the reaction mixture

was slowly warmed to room temperature, and subsequently HCl

(10%, 200 mL) and CH₂Cl₂were added. The separated aqueous

layer was extracted twice with CH₂Cl₂(200 mL each), and the com-

bined organic phases were dried with Na₂SO₄. Purification by col-

umn chromatography (silica gel, CH₂Cl₂/hexane, 2:8, R_f= 0.25)

1

delivered the product 10e (3.28 g, 62%) as a white solid. H NMR

(400 MHz, CDCl₃, 25 °C): δ = 7.44 (d, ⁴J = 2.4 Hz, 2 H, ArH),

7.28 (dd, ⁴J = 2.4 Hz, ³J = 8.7 Hz, 2 H, ArH), 6.78 (d, ³J = 8.7 Hz,

2 H, ArH), 3.99 (t, ³J = 6.6 Hz, 4 H, OCH₂), 3.22 (s, 2 H,

A r C ϵ C H ) , 1 . 8 0 ( m , 4 H , O C H ₂C H ₂) , 1 . 4 6 ( m , 4 H ,

OCH₂CH₂CH₂), 1.26 [s, 18 H, C(CH₃)₃], 1.23 (br. s, 52 H,

CH₂) ppm. ¹³C NMR (100.5 MHz, CDCl₃, 25 °C): δ = 158.0 (2 C,

ArC), 142.9 (2 C, ArC), 131.0 (2 C, ArCH), 127.1 (2 C, ArCH),

111.6 (2 C, ArCH), 110.9 (2 C, ArCCϵC), 80.7 (2 C, ArCϵC),

80.3 (2 C, ArCϵC), 68.9 (2 C, OCH₂), 34.0 [2 C, C(CH₃)₃], 31.3

[6 C, C(CH₃)₃], 29.7 (22 C, CH₂), 29.6 (2 C, CH₂), 29.4 (2 C, CH₂),

1

(262 mg, 63%). H NMR (400 MHz, CDCl₃, 25 °C): δ = 7.44 (d,

4

3

⁴J = 2.5 Hz, 2 H, ArH), 7.30 (dd, J = 2.5 Hz, J = 8.8 Hz, 2 H,

3

ArH), 6.76 (d, J = 8.8 Hz, 2 H, ArH), 3.96 (t, J = 6.5 Hz, 4 H,

OCH₂), 1.78 (m, 4 H, OCH₂CH₂), 1.44 (m, 4 H, OCH₂CH₂CH₂),

1.25 [s, 18 H, C(CH₃)₃], 1.24 (br. s, 28 H, CH₂), 0.20 [s, 18 H,

Si(CH₃)₃] ppm. ¹³C NMR (100.5 MHz, CDCl₃, 25 °C): δ = 159.8

(2 C, ArCCO), 143.2 (2 C, ArCC), 131.7 (2 C, ArCH), 128.4 (2 C,

ArCH), 111.7 (2 C, ArCH), 109.6 (2 C, ArC), 88.7 (2

C,CϵCCϵCCϵCTMS), 88.4 (2 C, CϵCCϵCCϵCTMS), 77.2 (2

C, CϵCCϵCCϵCTMS), 74.5 (2 C, CϵCCϵCCϵCTMS), 69.0 (2

C, OCH₂), 67.0 (2 C, CϵCCϵCCϵCTMS), 62.2 (2 C,

CϵCCϵCCϵCTMS), 34.1 [2 C, C(CH₃)₃], 31.3 [6 C, C(CH₃)₃],

29.7 (10 C, CH₂), 29.6 (2 C, CH₂), 29.3 (2 C, CH₂), 29.0 (2 C,

29.1 (2 C, CH ), 25.9 (2 C, CH ) ppm. IR (KBr): ν = 3443, 3310,

˜

2

3286, 2921, 2849, 2361, 1636, 1502, 1463, 1391, 1269, 1141, 1104,

819, 725, 635 cm^–1. UV/Vis (CH₂Cl₂): λ_max= 242, 249, 298,305 nm.

MS (FAB): m/z = 796 [M⁺]. C₅₆H₉₀O₂(795.28): calcd. C 84.57, H

11.41; found C 84.42, H 11.45.

1,40-Bis(4-tert-butyl-2-ethynylphenyloxy)tetracontane (10f): A solu-

tion of diisopropylamine (2.26 g, 22.38 mmol) in THF (56 mL) was

cooled to 0 °C, treated with a 1.6  solution of n-butyllithium

CH ), 25.9 (2 C, CH ), –0.5 [6 C, Si(CH ) ] ppm. IR (KBr): ν =

˜

2 2 3 3

2925, 2854, 2184, 2165, 2073, 1600,1498, 1467, 1408, 1364, 1330,

1290, 1252, 1168, 1131, 1100, 1018, 925, 849, 760, 704, 662,

1520

www.eurjoc.org

Eur. J. Org. Chem. 2006, 1508–1524

Synthesis of Alkylene-Bridged Diphenyl-Oligoynes

FULL PAPER

627 cm^–1. UV/Vis (hexane): λ_max= 217, 223, 235, 248, 260, 287,

306, 314, 333, 354 nm. MS (FAB): m/z = 892 [M⁺]. C₆₀H₈₂O₂Si₂

(891.44): calcd. C 80.84, H 9.27; found 80.54, H 9.12.

(d, J = 2.4 Hz, 2 H, ArH), 7.37 (dd, J = 2.4 Hz, J = 8.8 Hz, 2

4

3

H, ArH), 6.82 (d, J = 8.8 Hz, 2 H, ArH), 4.00 (t, J = 6.6 Hz, 4

H , O C H ₂) , 1 . 7 8 ( m , 4 H , O C H ₂C H ₂) , 1 . 4 4 ( m , 4 H ,

OCH₂CH₂CH₂), 1.27 (s, 68 H, CH₂), 1.26 [s, 18 H, C(CH₃)₃], 0.23

[s, 18 H, Si(CH₃)₃] ppm. ¹³C NMR (100.5 MHz, CD₂Cl₂, 25 °C): δ

= 160.3 (2 C, ArC), 143.7 (2 C, ArCC), 132.1 (2 C, ArCH), 129.1

(2 C, ArCH), 112.1 (2 C, ArCH), 109.5 (2 C, ArC), 89.5 (2

C,CϵCCϵCCϵCTMS), 88.2 (2 C, CϵCCϵCCϵCTMS), 77.2 (2

C, CϵCCϵCCϵCTMS), 75.1 (2 C, CϵCCϵCCϵCTMS), 69.4 (2

C, OCH₂), 67.2 (2 C, CϵCCϵCCϵCTMS), 62.1 (2 C,

CϵCCϵCCϵCTMS), 34.4 [2 C, C(CH₃)₃], 31.4 [6 C, C(CH₃)₃],

30.1 (30 C, CH₂), 30.0 (2 C, CH₂), 29.7 (2 C, CH₂), 29.4 (2 C,

1,32-Bis[4-tert-butyl-2-(6-trimethylsilylhexa-1,3,5-triynyl)phenyl-

oxy]dotriacontane (17b): A solution of 10e (1.00 g. 1.26 mmol) in

dry and degassed THF (32 mL) was cooled to 0 °C, treated with a

1.6  solution of n-butyllithium in hexane (1.57 mL, 2.52 mmol)

and stirred for 1 h at 0 °C. After removing the cooling bath, CuCl

(249 mg, 2.52 mmol) was added and stirred for 90 min at room

temperature, while an increasing turbidity and yellow coloration of

the solution was observed. Subsequently the reaction mixture was

concentrated to 10 mL at a rotatory pump vacuum and degassed

pyridine (20 mL) was added. When the residing THF was removed

in rotatory pump vacuo, a light green and almost clear solution

remained, which was cooled to 0 °C and treated with a solution of

1-bromo-4-(trimethylsilyl)buta-1,3-diyne (16, 0.75 g, 3.73 mmol) in

degassed THF (15 mL). The reaction process was controlled by

TLC (CH₂Cl₂/hexane, 1:9, R_f= 0.32). After 10 min aqueous HCl

(10%, 200 mL), water (200 mL) and hexane (250 mL) were added

and the phases separated. The aqueous phase was extracted twice

with hexane (200 mL each) and the combined organic layers dried

with Na₂SO₄. The product 17b was obtained as a pale yellow solid

(273 mg, 21%) by column chroamtography (silica gel, CH₂Cl₂/hex-

ane, 1:9). ¹H NMR (400 MHz, CDCl₃, 25 °C): δ = 7.44 (d, ⁴J =

CH ), 26.3 (2 C, CH ), –0.5 [6 C, Si(CH ) ] ppm. IR (KBr): ν =

˜

2

3 3

3448, 2922, 2849, 2186, 2167, 2074, 1600, 1498, 1470, 1409, 1390,

1364, 1331, 1290, 1253, 1166, 1130, 1100, 1015, 925, 892, 848, 815,

760, 720, 661, 627, 492 cm^–1. UV/Vis (CH₂Cl₂): λ_max= 226, 238,

249, 262, 316, 334, 356 nm. C₈₀H₁₂₂O₂Si₂(1171.96): calcd. C 81.98,

H 10.49; found C 81.35, H 10.68.

1,20-Bis[4-tert-butyl-2-(1,3,5-hexatriynyl)phenyloxy]eicosane (18a):

A spatulum tip of K₂CO₃was added to a solution of 17a (260 mg,

0.30 mmol) in a mixture of wet THF/MeOH (1:1, 4 mL). When

after 30 min only one product was observed by TLC control

(CH₂Cl₂/hexane, 2:8, R_f= 0.28), aqueous HCl (10%, 20 mL), water

(20 mL) and hexane (50 mL) were added. After separating the lay-

ers, the aqueous layer was extracted twice with hexane (50 mL

each) and the combined organic layers dried with Na₂SO₄. The

clear, slightly yellow solution was concentrated to a few mL and

immediately used for subsequent transformations to avoid decom-

position.

4

3

2.5 Hz, 2 H, ArH), 7.30 (dd, J = 2.5 Hz, J = 8.7 Hz, 2 H, ArH),

3

6.76 (d, J = 8.7 Hz, 2 H, ArH), 3.97 (t, J = 6.5 Hz, 4 H, OCH₂),

1.78 (m, 4 H, OCH₂CH₂), 1.45 (m, 4 H, OCH₂CH₂CH₂), 1.25 [s,

18 H, C(CH₃)₃], 1.24 (br. s, 52 H, CH₂), 0.20 [s, 18 H, Si(CH₃)₃]

ppm. ¹³C NMR (100.5 MHz, CDCl₃, 25 °C): δ = 159.9 (2 C,

ArCO), 143.2 (2 C, ArCC), 131.7 (2 C, ArCH), 128.3 (2 C,

ArCH), 111. 7 (2 C, ArCH), 109.7 (2 C, ArC), 88.7 (2

C,CϵCCϵCCϵCTMS), 88.4 (2 C, CϵCCϵCCϵCTMS), 77.2 (2

C, CϵCCϵCCϵCTMS), 74.5 (2 C, CϵCCϵCCϵCTMS), 69.0 (2

C, OCH₂), 67.0 (2 C, CϵCCϵCCϵCTMS), 62.2 (2 C,

CϵCCϵCCϵCTMS), 34.1 [2 C, C(CH₃)₃], 31.3 [6 C, C(CH₃)₃],

29.7 (22 C, CH₂), 29.6 (2 C, CH₂), 29.3 (2 C, CH₂), 29.1 (2 C,

1,32-Bis[4-tert-butyl-2-(1,3,5-hexatriynyl)phenyloxy]dotriacontane

(18b): To a solution of 17b (256 mg, 0.25 mmol) in a mixture of

wet THF/MeOH (1:1, 8 mL) a minute amount of K₂CO₃was

added. By TLC control (CH₂Cl₂/hexane, 2:8, R_f= 0.31) already

after 30 min the complete transformation was observed. Sub-

sequently, aqueous HCl (10%, 20 mL), water (20 mL) and hexane

(50 mL) were added and the two layers separated. The aqueous

layer was extracted twice with hexane (50 mL each) and the com-

bined organic layers were dried with Na₂SO₄. The resulting clear

and colourless solution was concentrated at room temperature to

10 mL and directly used for further reactions. At complete dryness

the product decomposed with black color within a few minutes.

CH ), 25.9 (2 C, CH ), –0.5 [6 C, Si(CH ) ] ppm. IR (KBr): ν =

˜

2

3 3

3444, 2923, 2850, 2353, 2187, 2167, 2075, 1601,1498, 1470, 1409,

1391, 1365, 1331, 1290, 1253, 1167, 1130, 1100, 1016, 925, 850,

760, 712, 662, 627, 493 cm^–1. UV/Vis (hexane): λ_max= 216, 223,

235, 248, 260, 288, 304, 313, 331, 353 nm. MS (FAB): m/z = 1036

[M⁺]. C₇₂H₁₀₆O₂Si₂(1059.75): calcd. C 81.60, H 10.08; found C

81.22, H 10.41.

1,40-Bis[4-tert-butyl-2-(1,3,5-hexatriynyl)phenyloxy]tetracontane

(18c): A solution of 17c (72 mg, 0.06 mmol) in a 1:1 mixture of

non-dried THF/MeOH (10 mL) was treated with a spatulum tip

of K₂CO₃. TLC control (CH₂Cl₂/hexane, 2:8, R_f= 0.35) showed

complete conversion after 30 min. Subsequently, water (150 mL)

and CH₂Cl₂(150 mL) were added and the layers separated. The

aqueous layer was extracted with CH₂Cl₂(80 mL), the combined

organic layers were washed with water (300 mL) and dried with

Na₂SO₄. The slightly yellow solution was concentrated to a few mL

and used directly for the next conversion without further charac-

terization.

1,40-Bis[4-tert-butyl-2-(6-trimethylsilylhexa-1,3,5-triynyl)phenyl-

oxy]tetracontane (17c): A suspension of the diyne 10f (500 mg,

0.55 mmol) in degassed and dry THF (13 mL) was treated with a

1.61  solution of butyllithium (0.71 mL, 1.13 mmol) in hexane at

0 °C. After 10 min the reaction was warmed to room temperature.

After 50 min, additional CuCl (112 mg, 1.13 mmol) was added and

a yellow-orange suspension was formed. Susequently, degassed pyr-

idine (8 mL) was added and cooled to 0 °C. Finally, 1-bromo-4-

(trimethylsilyl)buta-1,3-diyne (16, 320 mg, 1.59 mmol), dissolved in

degassed THF (7 mL), was added and the reaction progress con-

trolled by TLC (CH₂Cl₂/hexane, 2:8, R_f= 0.46). After 45 min, a

second portion of 1-bromo-4-(trimethylsilyl)buta-1,3-diyne (16,

162 mg, 0.80 mmol) was added and the mixture stirred at room

Dibenzo-dioxacycloalkanehexayne Derivative 19a: A solution of

CuCl (495 mg, 5.00 mmol) and TMEDA (238 mg, 2.05 mmol) in

acetone (30 mL) was stirred for 1 h and afterwards filtered three

temperature for 18 h. Subsequently, water (60 mL), HCl (10 %, times. The filter residues were washed with 3–4 mL of acetone,

60 mL) and hexane (250 mL) were added and the black-brown so-

lid tars removed by filtration. The two layers were separated, the

upper organic layer was washed with water (500 mL) and dried

with Na₂SO₄. The pure product 17c was obtained by column

each. A gentle stream of oxygen was passed through this dark violet

solution for 15 min. Subsequently, the as-prepared hexane solution

of 18a, diluted with acetone (80 mL), was added dropwise over a

period of 2.5 h. Afterwards, when no starting material was ob-

chromatography (silica gel, CH₂Cl₂/hexane, 12:88) as a pale yellow served anymore by TLC monitoring (CH₂Cl₂/hexane, 2:8, R_f=

solid (70 mg, 11%). ¹H NMR (400 MHz, CD₂Cl₂, 25 °C): δ = 7.47

0.64), water (30 mL), aqueous HCl (10 %, 30 mL) and hexane

Eur. J. Org. Chem. 2006, 1508–1524

www.eurjoc.org

1521

C. Klinger, O. Vostrowsky, A. Hirsch

FULL PAPER

(90 mL) were added and the two layers were allowed to separate.

The aqueous layer was extracted twice with hexane (70 mL each)

and the combined organic layers were washed twice with water

(200 mL each) and dried with Na₂SO₄. The product 19a was iso-

lated (72 mg, 33 %, relative to 17a) as a yellow oil by column

chromatography (silica gel, CH₂Cl₂/hexane, 1:9). ¹H NMR

of triethylamine (0.1 mL), [Pd(PPh₃)₂Cl₂] (0.80 mg, 1.0·10^–3mmol)

and CuI (0.45 mg, 2.3·10^–3mmol) in CH₂Cl₂over a period of 2 h.

After the addition was finished, TLC monitoring (CH₂Cl₂/hexane,

2:8) showed complete conversion. Only the hexayne 19c (R_f= 0.50)

and no other products were observed. Water (120 mL) and CH₂Cl₂

were added and the layers separated. The aqueous layer was ex-

tracted with CH₂Cl₂(50 mL) and the combined organic layers were

washed with water (300 mL) and dried with Na₂SO₄. By column

chromatography (silica gel, CH₂Cl₂/hexane, 1:9) the bright yellow-

4

(400 MHz, CD₂Cl₂, 25 °C): δ = 7.48 (d, J = 2.4 Hz, 2 H, ArH),

7.38 (dd, ⁴J = 2.6 Hz, ³J = 8.8 Hz, 2 H, ArH), 6.81 (d, ³J = 8.8 Hz,

ArH), 4.00 (t, ³J = 5.6 Hz, 4 H, OCH₂), 1.76 (m, 4 H, OCH₂CH₂),

1.52 (m, 4 H, OCH₂CH₂CH₂), 1.39 (m, 4 H, CH₂), 1.30 [s, 18 H,

orange zone of 19c was fractionated (35 mg, 58% relative to 17c)

C(CH₃)₃],1.26 (s, 24 H, CH₂) ppm. ¹³C NMR (100.50 MHz, as a yellow-orange oil. H NMR (400 MHz, CD₂Cl₂, 25 °C): δ =

1

CD₂Cl₂, 25 °C): δ = 161.2 (2 C, ArC), 143.8 (2 C, ArC), 132.0 (2

7.49 (d, ⁴J = 2.4 Hz, 2 H, ArH), 7.40 (dd, ⁴J = 2.6 Hz, ³J = 8.8 Hz,

3

C, ArCH), 129.7 (2 C, ArCH), 112.2 (2 C, ArCH), 109.0 (2 C, 2 H, ArH), 6.83 (d, J = 8.8 Hz, ArH), 4.01 (t, J = 6.3 Hz, 4 H,

A r C ) , 7 7 . 3 [ 2 C , ( A r C ϵ C C ϵ C C ϵ C ) ₂] , 7 5 . 8 [ 2 C , OCH₂), 1.79 (m, 4 H, OCH₂CH₂), 1.49 (m, 4 H, OCH₂CH₂CH₂),

( A r C ϵ C C ϵ C C ϵ C ) ₂] , 6 9 . 6 ( 2 C, O C H ₂) , 6 7 . 6 [ 2 C, 1.34–1.26 [m, 86 H, C(CH₃)₃and CH₂] ppm. ^{1 3}C NMR

(ArCϵCCϵCCϵC)₂], 64.9 [2 C, (ArCϵCCϵCCϵC)₂], 64.0 (100.50 MHz, CD₂Cl₂, 25 °C): δ = 161.0 (2 C, ArC), 143.8 (2 C,

[(ArCϵCCϵCCϵC)₂], 63.2 [2 C, (ArCϵCCϵCCϵC)₂], 34.4 [2 C,

C(CH₃)₃], 31.3 [8 C, C(CH₃)₃], 30.3 [2 C, CH₂], 30.2 (8 C, CH₂),

ArC), 132.2 (2 C, ArCH), 129.7 (2 C, ArCH), 112.1 (2 C, ArCH),

108.9 (2 C, ArC), 77.3 [2 C, (ArCϵCCϵCCϵC)₂], 76.0 [2 C,

29.9 (2 C, CH₂), 29.7 (2 C, CH₂), 29.4 (2 C, CH₂), 26.8 (2 C, ( A r C ϵ C C ϵ C C ϵ C ) ₂] , 6 9 . 4 ( 2 C, O C H ₂) , 6 7 . 6 [ 2 C,

CH ) ppm. IR (NaCl): ν = 2963, 2923, 2852, 2150, 2047, 1599,

(ArCϵCCϵCCϵC)₂], 65.0 [2 C, (ArCϵCCϵCCϵC)₂], 64.0

[(ArCϵCCϵCCϵC)₂], 63.3 [2 C, (ArCϵCCϵCCϵC)₂], 34.4 [2 C,

C(CH₃)₃], 31.4 [6 C, C(CH₃)₃], 29.9 (2 C, CH₂), 29.8 (2 C, CH₂),

29.7 (30 C, CH₂), 29.4 (2 C, CH₂), 26.4 (2 C, CH₂) ppm. IR (NaCl):

˜

2

1498, 1466, 1387, 1363, 1261, 1096, 1023, 804, 704, 625 cm^–1. MS

(FAB): m/z = 720 [M⁺]. UV/Vis (CH₂Cl₂): λ_max= 254, 265, 306,

317, 357, 379, 404, 438, 477 nm. C₅₂H₆₄O₂(721.03): calcd. C 86.61,

H 8.95; found C 85.79, H 8.99.

ν = 2962, 2922, 2854, 2151, 2047, 1601, 1499, 1462, 1387, 1362,

˜

1261, 1095, 1024, 805, 705, 624 cm^–1. UV/Vis (CH₂Cl₂): λ_max= 263,

276, 288, 304, 354, 373, 399, 435, 476 nm. MS (FAB): m/z = 1001

[M⁺]. C₇₂H₁₀₄O₂(1001.55): calcd. C 86.34, H 10.47; found C 85.76,

H 10.50.

Dibenzo-dioxacycloalkanehexayne Derivative 19b: A mixture of

CuCl (495 mg, 5.00 mmol) and TMEDA (0.31 mL, 2.05 mmol) in

acetone (30 mL) was stirred for 60 min. Subsequently, the suspen-

sion was filtered several times, until no precipitate was detected

anymore. After each of the filtrations, the filter residue was rinsed

with acetone (5 mL). The dark purple solution was flushed with

oxygen for 15 min. Subsequently, the hexane solution of 18b, di-

luted with acetone (80 mL), was added slowly and dropwise over a

period of 2 h. After another 2 h of stirring the TLC control showed

no more starting material (CH₂Cl₂/hexane, 2:8, R_f= 0.48), and

water (30 mL), aqueous HCl (10%, 30 mL) and hexane (90 mL)

were added and the layers allowed to separate. The aqueous layer

was extracted twice with hexane (70 mL each), and the combined

organic layers were washed twice with water (200 mL each) and

dried with MgSO₄. By means of column chromatography (silica

gel, CH₂Cl₂/hexane, 1:9) the yellow product zone was separated

and 19b was isolated (39 mg, 18 %) as a yellow oil. ¹H NMR

Dibenzo-dioxacycloalkaneoctayne Derivative 20: The bis(trimethyl-

silyltriyne) 17c (100 mg, 0.087 mmol) was deprotected with K₂CO₃

as described above for the bis(hexatriynes) 18a–c. The resulting

solution was diluted with CH₂Cl₂to a total of 5 mL. Subsequently,

1-bromo-4-(trimethylsilyl)buta-1,3-diyne (16) was added. Over a

period of 15 min, this mixture was added dropwise to a solution of

[Pd(PPh₃)₂Cl₂] (0.7 mg, 0.99·10^{– 3}mmol), CuI (0.5 mg,

2.60·10^–3mmol), triethylamine (727 mg, 7.20 mmol) and 1-bromo-

4-(trimethylsilyl)buta-1,3-diyne (16, 83 mg, 0.413 mmol) in CH₂Cl₂

(3 mL) at 0 °C. The reaction progress was controlled by TLC

(CH₂Cl₂/hexane, 2:8, R_f= 0.56). After every 22 h, [Pd(PPh₃)₂Cl₂]

(1.0 mg, 1.40·10^–3mmol) was added and after a total of 48 h, water

(100 mL) and CH₂Cl₂(100 mL) was added. The aqueous layer was

separated and extracted twice with CH₂Cl₂(50 mL each), the com-

bined organic layers were washed three times with water (100 mL

4

(400 MHz, CD₂Cl₂, 25 °C): δ = 7.49 (d, J = 2.4 Hz, 2 H, ArH),

7.40 (dd, ⁴J = 2.5 Hz, ³J = 8.6 Hz, 2 H, ArH), 6.83 (d, ³J = 8.9 Hz,

2 H, ArH), 4.01 (t, ³J = 6.3 Hz, 4 H, O–CH₂), 1.80 (m, 4 H, each) and dried with Na₂SO₄. By column chromatography (silica

OCH₂CH₂), 1.49 (m, 4 H, OCH₂CH₂CH₂), 1.28 [s, 18 H, C(CH₃)₃], gel, CH₂Cl₂/hexane, 1:9) the yellow product zone of 20 was sepa-

1.27 (s, 52 H, CH₂) ppm. ¹³C NMR (100.50 MHz, CD₂Cl₂, 25 °C):

rated in a yield of 1 mg (0.95·10^–3mmol, 1.1%). UV/Vis (CH₂Cl₂):

δ = 161.0 (2 C, ArC), 143.8 (2 C, ArC), 132.3 (2 C, ArCH), 129.8 λ_max= 292, 310, 326, 345, 364, 388, 409, 436, 472, 515 nm. MS

(2 C, ArCH), 112.5 (2 C, ArCH), 108.9 (2 C, ArC), 77.3 [2 C,

(ArCϵCCϵCCϵC)₂], 76.0 [2 C, (ArCϵCCϵCCϵC)₂], 69.4 (2 C,

O C H ₂) , 6 7 . 6 [ 2 C , ( A r C ϵ C C ϵ C C ϵ C ) ₂] , 6 4 . 9 [ 2 C,

(ArCϵCCϵCCϵC)₂], 64.1 [(ArCϵCCϵCCϵC)₂], 63.3 [2 C,

(ArCϵCCϵCCϵC)₂], 31.4 [2 C, C(CH₃)₃], 29.8 [6 C, C(CH₃)₃],

29.7 (24 C, CH₂), 29.6 (2 C, CH₂), 29.4 (2 C, CH₂), 26.4 (2 C,

(FAB): m/z = 1049 [M⁺].

Palladium-Catalyzed Coupling, Synthesis of Macrocyclic Oligoynes

23, 24, 15a and 25: A solution of the bis(acetylene) 10a (0.70 g,

1.36 mmol) in CH₃CN (8 mL) was added dropwise to a solution of

triethylamine (4.12 g, 40.80 mmol), [Pd(PPh₃)₂Cl₂] (9.5 mg,

13.6·10^–3mmol), CuI (5.2 mg, 27.0·10^–3mmol) and tetraiodoethene

(22, 1.45 g, 2.72 mmol) in CH₃CN (4 mL). After 3 h, when with

TLC control (CH₂Cl₂/hexane, 3:7) only traces of the starting mate-

rial were detectable, a saturated aqueous solution of NH₄Cl

(50 mL) and CH₂Cl₂(100 mL) were added. Subsequently, both lay-

ers were separated, the aqueous layer extracted twice with CH₂Cl₂

(100 mL each) and the combined organic phases were washed three

times with water (50 mL each) and dried with Na₂SO₄. By a two-

fold separation with column chromatography on silica gel (CH₂Cl₂/

hexane, 2:8 and 15:85) the diyne 23 (3 mg, 0.4%, R_f= 0.25), triyne

24 (28 mg, 3.8%, R_f= 0.32), tetrayne 15a (12 mg, 1.6%, R_f= 0.38)

CH ) ppm. IR (NaCl): ν = 2963, 2923, 2853, 2151, 2047, 1600,

˜

2

1499, 1464, 1386, 1362, 1260, 1096, 1024, 806, 705, 625 cm^–1. UV/

Vis (CH₂Cl₂): λ_max= 304, 316, 357, 379, 404, 437, 477 nm. UV/Vis

(hexane): λ_max= 303, 311, 351, 373, 398, 431, 470 nm. MS (FAB):

m/z = 888 [M⁺]. C₆₄H₈₈O₂(889.34): calcd. C 86.43, H 9.97; found

C 86.40, H 9.66.

Dibenzo-dioxacycloalkanehexayne Derivative 19c: The hexane solu-

tion of 18c was diluted with CH₂Cl₂to a total of 20 mL and 1-

bromo-4-(trimethylsilyl)buta-1,3-diyne (16, 50 mg, 0.250 mmol)

was added at 0 °C. This mixture was added dropwise to a solution

1522

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Eur. J. Org. Chem. 2006, 1508–1524

Synthesis of Alkylene-Bridged Diphenyl-Oligoynes

FULL PAPER

and pentayne 25 (traces, R_f= 0.43) were isolated (R_f-values deter-

[M⁺]. C₅₆H₈₈O₂(793.26): calcd. C 84.79, H 11.18; found C 84.38,

mined in CH₂Cl₂/hexane, 3:7).

H 11.35.

1

Dibenzo-dioxacycloalkanediyne Derivative 23: H NMR (400 MHz,

Palladium-Catalyzed Coupling, Synthesis of Macrocyclic Oligoynes

28 and 30

4

3

CDCl₃, 25 °C): δ = 7.51 (d, J = 2.6 Hz, 2 H, ArH), 7.28 (dd, J =

8.8 Hz, J = 2.6 Hz, 2 H, ArH), 6.77 (d, J = 8.8 Hz, ArH), 3.99

(t, J = 6.2 Hz, 4 H, OCH₂), 1.80 (m, 4 H, OCH₂CH₂), 1.49 (m, 4

4

3

Dibenzo-dioxacycloalkaneheptayne Derivative 28: To a solution of

17b (82 mg, 0.079 mmol) in a mixture of wet methanol/THF

(10 mL, 1:1) a minute amount of K₂CO₃was added and the mix-

ture stirred for 20 min. After this period, no more starting material

was detected by TLC (CH₂Cl₂/hexane, 2:8, R_f= 0.25), and water

(100 mL) and CH₂Cl₂(100 mL) were added. After separating the

organic layer, it was washed twice with water (300 mL each), dried

with Na₂SO₄, concentrated in vacuo to about 5 mL and diluted

with dry CH₂Cl₂(13 mL). Diiodoacetylene (27, 132 mg,

0.474 mmol) was added to this solution, and the mixture added

dropwise to a solution of [Pd(PPh₃)₂Cl₂] (0.6 mg, 0.85·10^–3mmol),

CuI (0.4 mg, 2.1·10^{– 3}mmol) and triethylamine (72 mg,

0.713 mmol) in CH₂Cl₂(6 mL) at –35 °C. By TLC monitoring only

the starting material was observed (CH₂Cl₂/hexane, 2:8). Sub-

sequently, the reaction mixture was warmed to room temperature

and stirred for 16 h. When no more starting material was detected

by TLC (CH₂Cl₂/hexane, 2:8, R_f= 0.30), hexane and water

(100 mL each) were added. After separating the layers, the aqueous

layer was extracted with hexane (50 mL) and the combined organic

phases were washed twice with water (150 mL each). After drying

with Na₂SO₄the yellow product fraction was purified and sepa-

rated from the simultanously formed hexayne 19b by column

chromatography (CH₂Cl₂/hexane, 1:9), yield 8 mg, 11 % of the

H, OCH₂CH₂CH₂), 1.33 (br. s, 12 H, CH₂), 1.27 [s, 18 H, C(CH₃)

₃] ppm. ¹³C NMR (100.50 MHz, CDCl₃, 22 °C): δ = 158.2 (2 C,

ArC), 142.8 (2 C, ArC), 131.6 (2 C, ArCH), 127.2 (2 C, ArCH),

111.3 (2 C, ArCH), 110.9 (2 C, ArC), 79.2 [2 C, (ArCϵC)₂], 77.4

[2 C, (ArCϵC)₂], 68.8 (2 C, OCH₂), 34.1 [2 C, C(CH₃)₃], 31.4 [6

C, C(CH₃)₃], 28.9 (4 C, CH₂), 28.5 (2 C, CH₂), 27.8 (2 C, CH₂),

26.1 (2 C, CH ) ppm. IR (KBr): ν = 2927, 1502, 1252, 1151,

˜

2

808 cm^–1. UV/Vis (CH₂Cl₂): λ_max= 246, 262, 278, 335, 355 nm. MS

(FAB): m/z = 512 [M⁺]. C₃₆H₄₈O₂(512.74): calcd. C 84.32, H 9.44;

found C 83.86, H 9.50.

Dibenzo-dioxacycloalkanetriyne Derivative 24: ¹H NMR (400 MHz,

4

3

CDCl₃, 22 °C): δ = 7.47 (d, J = 2.4 Hz, 2 H, ArH), 7.30 (dd, J =

4

3

8.7 Hz, J = 2.5 Hz, 2 H, ArH), 6.76 (d, J = 8.8 Hz, ArH), 3.99

(t, J = 5.4 Hz, 4 H, OCH₂), 1.76 (m, 4 H, OCH₂CH₂), 1.56 (m, 4

3

H, OCH₂CH₂CH₂), 1.36 (br. s, 12 H, CH₂), 1.26 [s, 18 H, C(CH₃)

₃] ppm. ¹³C NMR (100.50 MHz, CDCl₃, 22 °C): δ = 159.5 (2 C,

ArC), 143.0 (2 C, ArC), 131.5 (2 C, ArCH), 127.9 (2 C, ArCH),

111.5 (2 C, ArCH), 110.1 (2 C, ArC), 77.7 [2 C, (ArCϵCC)₂], 75.8

[2 C, (ArCϵCC)₂], 69.0 (2 C, OCH₂), 67.0 (2 C, ArCϵCC)₂, 34.2

[2 C, C(CH₃)₃], 31.4 [6 C, C(CH₃)₃], 29.2 (2 C, CH₂), 29.1 (2 C,

CH₂), 28.9 (2 C, CH₂), 28.8 (2 C, CH₂), 26.5 (2 C, CH₂) ppm. IR

(NaCl): ν = 2927, 2856, 2195, 1599, 1498, 1466, 1390, 1365, 1275,

˜

1

orange solid 28. H NMR (400 MHz, CD₂Cl₂, 25 °C): δ = 7.49 (d,

1147, 1049, 891, 816, 737, 627 cm^–1. UV/Vis (CH₂Cl₂): λ_max= 246,

261, 281, 331, 358, 385 nm. MS (FAB): m/z = 536 [M⁺]. C₃₈H₄₈O₂

(536.76): calcd. C 85.02, H 9.01; found C 84.99, H 8.99.

4

3

⁴J = 2.6 Hz, 2 H, ArH), 7.40 (dd, J = 2.6 Hz, J = 8.8 Hz, 2 H,

3

ArH), 6.83 (d, J = 8.9 Hz, 2 H, ArH), 4.01 (t, J = 6.2 Hz, 4 H,

OCH₂), 1.80 (m, 4 H, OCH₂CH₂), 1.49 (m, 4 H, OCH₂CH₂CH₂),

1.28 [s, 18 H, C(CH₃)₃], 1.27 (s, 52 H, CH₂) ppm. UV/Vis (CH₂Cl₂):

λ_max= 307, 324, 347, 372, 393, 419, 455, 496 nm. MS (FAB):

m/z = 913 [M⁺].

Dibenzo-dioxacycloalkanepentayne Derivative 25: UV/Vis (CH₂Cl₂):

λ_max= 278, 292, 307, 337, 356, 382, 412, 448 nm. MS (FAB):

m/z = 584 [M⁺].

Palladium-Catalyzed Coupling, Synthesis of Macrocyclic Oligoynes

26 and 19b: A solution of the bis(acetylene) 10e (200 mg,

0.25 mmol) in CH₂Cl₂(8 mL) was added dropwise to a solution of

triethylamine (4.12 g, 40.80 mmol), [Pd(PPh₃)₂Cl₂] (21 mg,

0.03 mmol), CuI (12 mg, 0.06 mmol) and tetraiodoethene (22,

804 mg, 1.51 mmol) in acetonitrile (4 mL). After 3 h, when by TLC

control (CH₂Cl₂/hexane, 2:8) only traces of the starting material

were detectable, a saturated aqueous solution of NH₄Cl (50 mL)

and CH₂Cl₂(50 mL) were added. Subsequently, the layers were sep-

arated, the aqueous layer was extracted twice with CH₂Cl₂(50 mL

each) and the combined organic phases were washed three times

with water (100 mL each) and dried with Na₂SO₄. By column

chromatography on silica gel (CH₂Cl₂/hexane, 16:84) the diyne 26

(10 mg, 5%, white solid) and the hexayne 19b (7 mg, 3%) were

isolated.

Phenylenediyne Macrocycle 30: A solution of 10a (100.0 mg,

0.195 mmol) and 1,4-diiodobenzene (29, 64.2 mg, 0.195 mmol) in

CH₂Cl₂(15 mL) was added dropwise to a solution of [Pd(PPh₃)₂-

Cl₂] (1.4 mg, 1.94·10^–3mmol), CuI (0.8 mg, 3.9·10^–3mmol) and tri-

ethylamine (2 mL) in CH₂Cl₂(15 mL) and stirred for 18 h. Only

traces of starting material were detected by TLC control (CH₂Cl₂/

hexane, 3:7, R_f= 0.43), and a saturated aqueous solution of NH₄Cl

(50 mL) and CH₂Cl₂(100 mL) were added. After separating the

two layers, the aqueous layer was extracted twice with CH₂Cl₂

(100 mL each) and the combined organic layers were washed three

times with water (50 mL each) and dried with Na₂SO₄. The pheny-

lenediyne 30 was isolated as a white solid by column chromatog-

raphy (silica gel, CH₂Cl₂/hexane, 3:7) in 26 % (30 mg) yield. ¹H

NMR (400 MHz, CDCl₃, 25 °C): δ = 7.50 (s, 4 H, CϵCArHCϵC)

7.47 (d, ⁴J = 2.4 Hz, 2 H, ArH), 7.28 (dd, ³J = 8.7 Hz, ⁴J = 2.4 Hz,

1

3

Dibenzo-dioxacycloalkanediyne Derivative 26: H NMR (400 MHz,

2 H, ArH), 6.80 (d, J = 8.7 Hz, 2 H, ArH), 4.02 (t, J = 5.2 Hz,

4

CD₂Cl₂, 25 °C): δ = 7.50 (d, J = 2.8 Hz, 2 H, ArH), 7.34 (dd, J 4 H, OCH₂), 1 . 7 8 ( m, 4 H , O CH₂CH₂), 1. 65 (m, 4 H,

= 2.7 Hz, ³J = 8.8 Hz, 2 H, ArH), 6.84 (d, J = 8.8 Hz, ArH), 4.04 OCH₂CH₂CH₂), 1.37–1.30 (br., 12 H, CH₂), 1.29 [s, 18 H, C(CH₃)₃]

3

(t, J = 6.6 Hz, 4 H, OCH₂), 1.85 (m, 4 H, OCH₂CH₂), 1.49 (m, 4 ppm. ¹³C NMR (100.5 MHz, CDCl₃, 25 °C): δ = 157.8 (2 C, ArC),

3

H, OCH₂CH₂CH₂), 1.39–1.25 (m, 52 H, CH₂), 1.29 [s, 18 H, C– 143.1 (2 C, ArC), 131.3 (2 C, CϵCArCHCϵC), 129.9 (2 C, ArCH),

(CH₃)₃] ppm. ¹³C NMR (100.50 MHz, CD₂Cl₂, 25 °C): δ = 159.2 126.8 (2 C, ArCH), 123.3 (2 C, CϵCArCCϵC) 112.1 (2 C, ArC),

(2 C, ArC), 143.6 (2 C, ArC), 131.6 (2 C, ArCH), 128.1 (2 C,

ArCH), 112.1 (2 C, ArCH), 111.0 (2 C, ArC), 79.6 [2 C, (ArCϵC)₂], ArCCϵCArC), 68.9 (2 C, OCH₂), 34.1 [2 C, C(CH₃)₃], 31.4 [6C,

77.4 [2 C, (ArCϵC)₂], 69.3 (2 C, OCH₂), 34.3 [2 C, C(CH₃)₃], 31.5 C(CH₃)₃], 30.4 (2 C, CH₂), 30.0 (2 C, CH₂), 29.9 (2 C, CH₂), 29.7

[6 C, C(CH₃)₃], 29.9 (12 C, CH₂), 29.8 (2 C, CH₂), 29.7 (2 C, CH₂), (2 C, CH ), 27.1 (2 C, CH ) ppm. IR (NaCl): ν = 2957, 2923, 2853,

111.5 (2 C, ArCH), 92.8 (2 C, ArCϵCArC), 88.3 (2 C,

˜

2

29.6 (2 C, CH₂), 29.5 (2 C, CH₂), 29.4 (2 C, CH₂), 29.3 (2 C, CH₂), 1740, 1618, 1595, 1499, 1466, 1406, 1386, 1363, 1341, 1289, 1259,

29.2 (2 C, CH₂), 29.1 (2 C, CH₂), 26.3 (2 C, CH₂) ppm. UV/Vis

(hexane): λ_max= 246, 263, 278, 334, 356 nm. MS (FAB): m/z = 793

1162, 1096, 1026, 891, 810, 751, 737, 629, 545 cm^–1. UV/Vis

(CH₂Cl₂): λ_max[nm] = 227, 301, 344, 364 nm. MS (FAB): m/z = 588

Eur. J. Org. Chem. 2006, 1508–1524

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1523

C. Klinger, O. Vostrowsky, A. Hirsch

FULL PAPER

[M⁺]. C₄₂H₅₂O₂(588.84): calcd. C 85.66, H 8.90; found C 85.14, H

8.94.

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Acknowledgments

We thank the Fonds der Chemischen Industrie for financial sup-

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Received: October 31, 2005

Published Online: January 24, 2006

8, 1279–1285.

1524

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Article Doi

Synthesis of alkylene-bridged diphenyl-oligoynes

DOI: 10.1002/ejoc.200500851

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