New 1,3-disubstituted enantiomerically pure allylboronic esters by Johnson rearrangement of boron-substituted allyl alcohols

Article abstract of DOI:10.1002/ejoc.200400572

Starting from commercially available 1-substituted propargylic alcohols 6, 18 and ent-18, stable enantio- and diastereomerically pure 1,3-disubstituted allylboronic esters 10, 19 and 20 were synthesized. The key step - a Johnson rearrangement - was highly

Full text of DOI:10.1002/ejoc.200400572

FULL PAPER
New 1,3-Disubstituted Enantiomerically Pure Allylboronic Esters by Johnson
Rearrangement of Boron-Substituted Allyl Alcohols
Jörg Pietruszka*[a] Niklas Schöne[a]
Dedicated to the memory of Prof. Dr. W. A. König
Keywords: Sigmatropic reactions / Rearrangements / Allylation reactions / Boronic esters / Stereoselectivity
Starting from commercially available 1-substituted propar- 10 and its diastereomer 11 were independently synthesized
gylic alcohols 6, 18 and ent-18, stable enantio- and diastere-
omerically pure 1,3-disubstituted allylboronic esters 10, 19
and 20 were synthesized. The key step − a Johnson re-
arrangement − was highly diastereoselective and yielded the
products with almost complete transfer of the stereogenic in-
formation from the intermediate allyl alcohols. The config-
by cross-metathesis of the known boronates 2a and 3a with
styrene) or by analysis of the NMR data, and additionally by
X-ray structural analysis (of 20). Allyl addition to benzal-
dehyde in all cases yielded enantiomerically highly enriched
homoallylic alcohols 15/ent-15 and 21/ent-21 (Ͼ 98% ee).
urations of all the new derivatives were unequivocally as- ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
signed either by chemical correlation (e.g. allylboronic ester
Germany, 2004)
Introduction
The enantio- and diastereoselective allyl addition of allyl-
boronic esters to carbonyl groups to give homoallyl al-
cohols is one of the most versatile transformations in
organic synthesis. Since the transition structure is well
defined, the outcome of such reactions is often
predictable.[1Ϫ6] Reagents with a stereogenic center in the
position α to the boronic ester moiety are special: While the
selectivity of the addition is often exceptionally high, their
applicability in this reaction is sometimes hampered
by problems when synthesizing enantiomerically pure
derivatives.[7Ϫ43] Incorporating additional functional groups
into these compounds is even more difficult. Recently, we
established a new route to homoallyl alcohols starting from
the readily available allyl alcohol 1: [3,3] sigmatropic re-
arrangements[44,45] yielded either the easily separable ester
2a/3a (Johnson rearrangement[46]) or the amide 2b/3b
(Eschenmoser rearrangement[47,48]) in good yield.[49] The
subsequent allyl addition proved to be highly enantioselec-
tive furnishing homoallyl alcohols 4; in all cases the (Z)
product was exclusively formed (Scheme 1). In order to ex-
tend this approach, we were interested in introducing ad-
ditional substituents into the 5-position of the allylboronic
esters and ultimately into the hydroxy esters 5. In this first
investigation we focused on the synthesis and structural
Scheme 1. Synthesis of new enantiomerically pure reagents 2 and
3 for allylations by a [3,3] sigmatropic rearrangement
assignment of phenyl and methyl derivatives (R2 ϭ Ph or
Me).
Results and Discussion
5-Phenyl Derivatives
First, 1-phenyl-2-propyn-1-ol (6) was used as a con-
venient starting material: Silyl-protection with tert-butyldi-
methylsilyl chloride (TBSCl) yielded 7 (97%) as the starting
material for a one-pot hydroboration-oxidation-transesteri-
[a]
Institut für Organische Chemie der Universität Stuttgart,
Pfaffenwaldring 55, 70569 Stuttgart, Germany
Fax: (internat:) ϩ 49-711-685-4329
E-mail: joerg.pietruszka@oc.uni-stuttgart.de
Eur. J. Org. Chem. 2004, 5011Ϫ5019
DOI: 10.1002/ejoc.200400572
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
5011

J. Pietruszka, N. Schöne
FULL PAPER
fication[22] reaction (68%) that had previously been estab-
In view of the complete transfer of the stereogenic infor-
lished (Scheme 2).[50] The stable[51,52] alkenylboronic ester mation from pure allyl alcohol 9 to allylboronic ester 10, it
8 was deprotected under acidic conditions to furnish the was questioned whether the chiral ‘‘diol’’ protecting
envisaged allyl alcohol 9 (78%). Under typical conditions group[51,55] could be replaced by a robust achiral diol such
of the Johnson rearrangement, this new substrate was con- as benzpinacol. We had previously demonstrated that this
verted in high yield (82%) to the 1,3-disubstituted allylbo- type of boronic ester has a similar stability to that of chiral
ronic ester 10. No trace of diastereoisomer 11 could be de- enantiomerically pure derivatives.[40,56] However, although
tected in the crude product. Note that the NMR chemical its synthesis by the established sequence proved feasible, the
shifts for these two diastereoisomers are distinctly different, yields were in most cases distinctly lower (Scheme 3). In
especially for 4-H/C-4 (downfield shifted for 10); hence the particular, the synthesis of the alkenylboronic ester 12 was
NMR data should be diagnostic for a series of related re- troublesome and only minimum amounts of product were
agents, as can also be seen when comparing these data with isolated (27%). While the deprotection to 13 worked well
those of the parent derivatives 2a and 3a. To assign the (82%), the yield of the rearrangement to allylboronic ester
absolute configurations of 10 and 11 at C-3, independent 14 was moderate (48%). At this stage no definite statement
cross-metatheses were performed:[53,54] With styrene and with regards the enantiomeric excess could be made.
the known 2a and 3a as substrates, both diastereoisomers
The degree of enantiomeric purity of allylboronic ester
10 and 11 were obtained in the pure form, though in rela- 14 was deduced by performing allyl addition with benzal-
tively poor yield (53 and 45%, respectively).
dehyde (Scheme 4): Pure diastereoisomers 10 and 11 each
Scheme 3. Synthesis of benzpinacol-derived allylboronic ester 14
Scheme 4. Allyl additions of reagents 10, 11 and 14; the absolute
and relative configuration of homoallyl alcohol 15 was established
by chemical correlation with known diol 16 and dioxaborinane 17
Scheme 2. Synthesis of allylboronic esters 10 and 11; determination
of their absolute configurations
5012
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
Eur. J. Org. Chem. 2004, 5011Ϫ5019

New 1,3-Disubstituted Enantiomerically Pure Allylboronic Esters
FULL PAPER
gave only one homoallyl alcohol 15 or ent-15, respectively, and 4-H) and finally unambiguously by X-ray structural
the configuration of the double bond being Z in both cases. analysis[58] of boronic ester 20.
The enantiomeric excesses were determined by means of
Finally, allyl addition of crotylboronic esters 19 and 20
HPLC using a chiral stationary phase (Ͼ 99% ee). While to benzaldehyde furnished slightly impure homoallyl al-
the yield for the allyl addition with 14 was also good (84%), cohols 21 and ent-21 in 95 and 90% yields, respectively
the enantiomeric excess of 15 was lower (91% ee). Since the (Scheme 6). Again, the (Z) diastereoisomers were the sole
(Z) diastereoisomer was again exclusively formed, it is products. These results are in full agreement with those pre-
highly likely that the allyl addition was Ϫ as expected Ϫ dicted for the proposed transition states of bulky allylbo-
completely selective, while the previous step, the rearrange- ronic esters (the α-substituent is preferentially axial!) by
ment, was not. To verify the absolute and relative configu- Hoffmann and Weidmann.[7] The relative and absolute con-
rations of 15, we converted the homoallyl alcohol to the figurations of the two newly formed stereogenic centers
known diol 16[57] by an ozonolysis-reduction reaction se- were assigned by ozonolysis and reduction to the known
quence (57%). Condensation of an analytical sample of diol anti-diols 22 and ent-22,[59][60] respectively, and by forma-
16 with phenylboronic acid furnished dioxaborinane 17; the tion of the dioxaborinane 23 (which has a characteristic
observed coupling constant (3J4,5 ϭ 9.8 Hz) also confirmed 3J4,5 coupling constant of 9.7 Hz). Although the enantiom
the relative configuration.[57] The optical rotation of diol 16 eric purities of 21/22 and ent-21/22 could not be determined
gave the absolute configuration.
by direct methods completely satisfactorily (complete base-
line separation of enantiomers by GLC or HPLC using chi-
ral stationary phases was not possible), the ee values were
confirmed from the optical rotations to be at least Ͼ 98%
ee in both cases.
5-Methyl Derivatives
From the point of view of potential synthetic targets, the
crotyl series is more versatile. Starting from the readily
available 3-butyn-2-ols (18 and ent-18), the established reac-
tion sequence furnished the diastereomerically pure crotyl-
boronic esters 19 and 20, respectively (Scheme 5): After silyl
protection (85/79%), hydroboration-oxidation-transesterifi-
cation and deprotection (56/50% over 2 steps), Johnson re-
arrangement yielded the reagents (78/80%). In both cases
only one diastereoisomer was detected by NMR spec-
troscopy of the crude product. The configuration of com-
pounds 19 and 20 at C-3 was deduced by analogy from
analysis of the NMR data (relative chemical shifts of C-4
Scheme 6. Allyl additions of reagents 19 and 20; the absolute and
relative configurations of homoallyl alcohol 21/ent-21 was estab-
lished by chemical correlation with known diol 22/ent-22 and diox-
aborinane 23
Conclusions
For the first time 1,3-disubstituted enantiomerically pure
allylboronic esters 10, 19 and 20 were synthesized by a com-
pletely selective Johnson rearrangement of boron-contain-
ing allyl alcohols (e.g. 9). Furthermore, diastereoisomer 11
(as well as 10 from 2a) was obtained after cross-metathesis
Scheme 5. Synthesis of crotylboronic esters 19 and 20; the absolute
configuration of reagent 20 was established by X-ray structural
analysis
Eur. J. Org. Chem. 2004, 5011Ϫ5019
www.eurjoc.org
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
5013

J. Pietruszka, N. Schöne
FULL PAPER
Alkenylboronic Ester 9: Under dry nitrogen, BH3·SMe2 complex
(100 µL of a 10  solution in dimethyl sulfide, 1.00 mmol) in 1,2-
dimethoxyethane (1 mL; DME) was stirred at room temperature.
After addition of cyclohexene (203 µL, 164 mg, 2.00 mmol), a col-
orless precipitate formed within 1 h; alkyne 7 (246 mg, 1.00 mmol)
was then added. Stirring was continued until a clear solution
formed. First, trimethylamine N-oxide dihydrate[62Ϫ64](222 mg,
2.00 mmol; water was removed prior to addition by DeanϪStark
distillation with toluene) and after 1 h the ‘‘diol’’ (455 mg,
1.00 mmol) was added. The reaction mixture was stirred until no
further consumption (as judged by TLC) of diol was indicated. The
solvent was removed under reduced pressure and the crude product
subjected to flash-column chromatography on silica gel (petroleum
ether/ethyl acetate, 98:2). Yield of 8: 483 mg (0.68 mmol, 68%), col-
orless foam. This silyl ether was deprotected by dissolving alkenyl-
boronic ester 8 (483 mg, 0.68 mmol) in a minimum amount of
CH2Cl2 and ethanol (7.64 mL). Concentrated hydrochloric acid
(159 µL) in ethanol (1.43 mL) was then added dropwise. After 1 h,
complete consumption (as judged by TLC) of the starting material
was detected. Saturated aqueous sodium hydrogencarbonate
(2.50 mL) was added and the volume of the solvent reduced under
reduced pressure. Water was added and the aqueous layer extracted
with Et2O (3 ϫ 20 mL). The combined organic layers were washed
with saturated brine, dried with MgSO4 and subjected to flash-
column chromatography on silica gel (petroleum ether/ethyl acet-
ate, 85:15). Yield of 9: 318 mg (0.53 mmol, 78%), colorless foam.
Softening range 79Ϫ93 °C. [α]2D0 ϭ Ϫ16 (c ϭ 1.12, CHCl3). IR
(KBr): ν˜ ϭ 3560, 3070, 3040, 3005, 2960, 2940, 2920, 2880, 2805,
1630, 1590, 1570, 1480, 1435, 1390, 1365, 1340, 1310, 1270, 1225,
1160, 1060 cmϪ1. MS (FAB, NBA ϩ NaI): m/z (%) ϭ 619 (11) [M
ϩ Na]ϩ, 197 (100) [CPh2OMe]ϩ. 1H NMR (500 MHz, CDCl3): δ ϭ
1.83 (d, J ϭ 3.9 Hz, 1 H, OH), 2.99 (s, 6 H, OCH3), 5.02 (ddd, J ϭ
5.1, J ϭ 3.9, J ϭ 1.6 Hz, 1 H, 1-H), 5.35 (s, 2 H, 4Ј-H, 5Ј-H), 5.37
(dd, J ϭ 18.0, J ϭ 1.6 Hz, 1 H, 3-H), 6.28 (dd, J ϭ 18.0, J ϭ
5.1 Hz, 1 H, 2-H), 7.16Ϫ7.34 (m, 25 H, arom. CH) ppm. 13C NMR
(125 MHz, CDCl3): δ ϭ 51.8 (OCH3), 75.8 (C-1), 77.6 (C-4Ј, C-
5Ј), 83.3 (CPh2OMe), 116.5 (C-3), 126.5, 127.2, 127.2, 127.5, 127.8,
127.8, 128.4, 128.4, 129.7 (arom. CH), 141.0, 141.2, 141.9 (arom.
of the known boronic ester 3a, thus allowing the absolute
configurations of these products to be established. For the
crotyl series, X-ray structural analysis of 20 allowed the un-
ambiguous assignment of its configuration. All the allyl ad-
ditions proved highly selective giving Z-configured homoal-
lyl alcohols with Ͼ 98% ee. These results should be the basis
for the future development of a plethora of highly selective
and stable storable allylboronic esters.
Experimental Section
General Remarks: All reagents were used as purchased from com-
mercial suppliers without further purification. The reactions were
carried out by using standard Schlenk techniques under dry nitro-
gen. Glassware was oven-dried at 112 °C overnight. Solvents were
dried and purified by conventional methods prior to use; diethyl
ether (Et2O), 1,2-dimethoxyethane (DME), and tetrahydrofuran
(THF) were freshly distilled from sodium/benzophenone. Petro-
leum ether refers to the fraction with a boiling point between
40Ϫ60 °C. Flash-column chromatography: Merck silica gel 60,
0.040Ϫ0.063 mm (230Ϫ400 mesh). TLC: Pre-coated sheets, Polyg-
ram SIL G/UV254 MachereyϪNagel; detection by UV or by ce-
rium molybdenum solution [phosphomolybdic acid (25 g),
Ce(SO4)2·H2O (10 g), concd. H2SO4 (60 mL), H2O (940 mL)]. Pre-
parative MPLC: Labomatic (MD80/100) with a packed column (39
ϫ 400 mm or 23 ϫ 250 mm), LiChroprep, Si60 (15Ϫ25 µm) and
UV detector (254 nm). HPLC: Pharmacia, equipped with a CHIR-
1
ALCEL OD column. H and 13C NMR spectra were recorded at
room temperature in CDCl3 with a Bruker ARX 500/300. Chemical
shifts δ are given in ppm relative to TMS as internal standard or
relative to the resonance of the solvent (13C: CDCl3, δ ϭ 77.0 ppm);
coupling constants J are given in Hz. Higher order δ and J values
are not corrected. 13C signals were assigned by means of CϪH and
HϪH COSY spectroscopy. Microanalyses were performed at the
Institut für Organische Chemie, Stuttgart. Melting points (Büchi
510) are not corrected. Specific rotations were measured at 20 °C
unless otherwise stated.
C
ipso), 153.1 (C-2) ppm. C39H37BO5 (596.52): calcd. C 78.53, H
X-ray Crystallographic Analysis:[58] The crystal data for compound
20 were determined with a Siemens P4 diffractometer with graphite
monochromator in the ω-scan mode with Cu-Kα (λ ϭ 1.54178 A)
6.25; found C 78.36, H 6.30.
Allylboronic Ester 10. Method A (Johnson Rearrangement): Allyl
alcohol 9 (276 mg, 0.46 mmol), triethyl orthoacetate (525 mg,
3.24 mmol) and propionic acid (2 mg, 2 µL, 0.03 mmol) were
placed in an oven-dried flask equipped with a magnetic stirrer bar
and a Claisen condenser. The mixture was stirred at 135 °C for
3 h. After cooling to room temperature, the residue was co-distilled
several times with CH2Cl2 to remove the orthoester and propionic
acid. After flash-column chromatography on silica gel (petroleum
ether/ethyl acetate, 95:5) the product was obtained. Yield of 10:
253 mg (0.38 mmol, 82%), colorless foam. Method B (Cross-
Metathesis): Under dry N2, allylboronic ester 2a[49] (207 mg,
˚
radiation. C38H41BO6, Mr ϭ 604.5, colorless, T ϭ 293 K, crystal
size 0.35 ϫ 0.25 ϫ 0.1 mm, orthorhombic, P212121, a ϭ 9.3668(6),
3
˚
˚
b ϭ 17.7165(17), c ϭ 19.9587(16) A, V ϭ 3312.1(5) A , Z ϭ 4,
D
calcd. ϭ 1.212 g·cmϪ3, µ ϭ 0.641 mmϪ1, F(000) ϭ 1288, θ range ϭ
3.34Ϫ64.99°, 3524 measured/independent reflections, 2162 reflec-
tions with [I Ͼ 2σ(I)]. The structure was solved by direct methods
and refined by full-matrix least squares on F2 for all data weights
to R ϭ 0.098, wR ϭ 0.199(6), S ϭ 1.030, H atoms were treated as
riding atoms, max. shift/error Ͻ 0.001, residual ρmax. ϭ 0.248 AϪ3
.
(R)-tert-Butyldimethyl(1-phenylprop-2-ynyloxy)silane (7): Under 0.35 mmol) was dissolved in CH2Cl2 (3.5 mL) in a 25-mL Schlenk
dry nitrogen, alcohol 6 (400 mg, 3.02 mmol) was dissolved in flask equipped with a magnetic stirrer bar and a reflux condenser.
CH2Cl2 (2.5 mL) and imidazole (226 mg, 3.32 mmol) was added Styrene (81 µL, 73 mg, 0.70 mmol) and ‘‘Grubbs-II catalyst’’
at 0 °C. After addition of tert-butyldimethylsilyl chloride (456 mg,
3.02 mmol; TBSCl), the mixture was stirred for 5 h. Hydrolysis
(30 mg, 35 µmol) was added and the mixture heated to 40 °C. The
reaction was incomplete (as judged by TLC) after 22 h; however,
with water (2.5 mL) was followed by extraction with pentane (3 ϫ neither addition of styrene (323 µL, 292 mg, 2.81 mmol) nor cata-
10 mL). The combined organic layers were dried with MgSO4, fil-
tered and the solvents removed under reduced pressure. The crude
lyst (6 mg, 7 µmol) changed the product distribution. After 2 d,
the volatiles were removed under reduced pressure and the residue
product was purified by flash-column chromatography (pentane/ subjected first to flash-column chromatography on silica gel (petro-
Et2O, 98:2); the experimental data are in full agreement with those
leum ether/ethyl acetate, 95:5) and then MPLC (petroleum ether/
ethyl acetate, 95:5). Yield of 10: 125 mg (0.19 mmol, 53%). Soften-
ing range 44Ϫ61 °C. [α]2D0 ϭ Ϫ20 (c ϭ 1.00, CHCl3). IR (KBr):
previously reported.[61] Yield: 724 mg (2.94 mmol, 97%), yellowish
oil.
5014
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
Eur. J. Org. Chem. 2004, 5011Ϫ5019

New 1,3-Disubstituted Enantiomerically Pure Allylboronic Esters
ν˜ ϭ 3070, 3040, 3010, 2960, 2920, 2880, 2810, 1730, 1630, 1590, m/z (%) ϭ 645 (13) [M ϩ Na]ϩ. 1H NMR (300 MHz, CDCl3): δ ϭ
FULL PAPER
1570, 1480, 1435, 1360, 1265, 1220, 1190, 1120, 1060 cmϪ1. MS
Ϫ0.07, 0.05 [2 s, 6 H, Si(CH3)2], 0.87 [s, 9 H, C(CH3)3], 5.27 (dd,
(FAB, NBA ϩ NaI): m/z (%) ϭ 689 (27) [M ϩ Na]ϩ, 197 (100) J ϭ 4.6, J ϭ 1.5 Hz, 1 H, 1-H), 6.03 (dd, J ϭ 17.8, J ϭ 1.7 Hz, 1
[CPh2OMe]ϩ. 1H NMR (500 MHz, CDCl3): δ ϭ 1.10 (t, J ϭ H, 3-H), 6.94Ϫ7.34 (m, 26 H, 2-H, arom. CH) ppm. 13C NMR
7.1 Hz, 3 H, 2ЈЈ-H), 2.07Ϫ2.21 (m, 3 H, 2-H, 3-H), 3.00 (s, 6 H,
(125 MHz, CDCl3): δ ϭ Ϫ4.8, Ϫ4.6 [Si(CH3)2], 18.4 [C(CH3)3],
OCH3), 3.92 (dq, J ϭ 10.8, J ϭ 7.1 Hz, 1 H, 1ЈЈ-Ha), 3.93 (dq, J ϭ 25.9 [C(CH3)3], 76.7 (C-1), 95.9 (CPh2), 115.1 (C-3), 126.4, 126.9,
10.8, J ϭ 7.1 Hz, 1 H, 1ЈЈ-Hb), 5.34 (s, 2 H, 4Ј-H, 5Ј-H), 5.88 (dd, 126.9, 127.2, 127.3, 128.3, 128.5 (arom. CH), 142.6, 142.5, 142.8
J ϭ 16.0, J ϭ 7.0 Hz, 1 H, 4-H), 6.08 (d, J ϭ 16.0 Hz, 1 H, 5-H), (arom. Cipso), 157.3 (C-2) ppm. C41H43BO3Si (622.67): calcd. C
7.10Ϫ7.33 (m, 25 H, arom. CH) ppm. 13C NMR (125 MHz,
79.08, H 6.96; found C 78.90, H 6.97. The silyl ether was depro-
CDCl3): δ ϭ 14.2 (OCH2CH3), 24.4 (C-3), 34.0 (C-2), 51.7 (OCH3), tected by dissolving alkenylboronic ester 12 (188 mg, 0.30 mmol)
60.1 (OCH2CH3), 78.0 (C-4Ј, C-5Ј), 83.3 (CPh2OMe), 125.9, 126.5, in a minimum amount of CH2Cl2 and ethanol (7.64 mL). Concen-
127.3, 127.4, 127.6, 127.8, 128.3, 128.4, 129.6 (arom. CH), 128.6 trated hydrochloric acid (159 µL) in ethanol (1.43 mL) was then
(C-5), 129.7 (C-4), 137.9, 141.0, 141.0 (arom. Cipso), 172.9 (C-1) added dropwise. After 1 h, complete consumption (as judged by
ppm. C43H43BO6 (666.61): calcd. C 77.48, H 6.50; found C 77.43,
H 6.76.
TLC) of the starting material was detected. Saturated aqueous so-
dium hydrogencarbonate (637 µL) was added and the volume of
the solvent reduced under reduced pressure. Water was added and
the aqueous layer extracted with Et2O (3 ϫ 20 mL). The combined
organic layers were washed with saturated brine, dried with MgSO4
and subjected to flash-column chromatography on silica gel (petro-
leum ether/ethyl acetate, 85:15) to furnish the spectroscopically
pure product. Yield of 13: 129 mg (0.25 mmol, 82%), colorless
foam. An analytical sample was further purified by MPLC (petro-
leum ether/ethyl acetate, 85:15). M.p. 156Ϫ158 °C. [α]2D0 ϭ ϩ17
(c ϭ 1.10, CHCl3). IR (KBr): ν˜ ϭ 3550, 3400, 3070, 3040, 3010,
2980, 1630, 1590, 1575, 1480, 1435, 1385, 1350, 1320, 1295, 1270,
1220, 1210, 1160, 1060 cmϪ1. MS (CI, CH4: Tsource ϭ 410 K, Tsam-
Allylboronic Ester 11. Method B (Cross-Metathesis): Under dry N2,
allylboronic ester 3a (200 mg, 0.34 mmol) was dissolved in CH2Cl2
(3.4 mL) in a 25-mL Schlenk flask equipped with a magnetic stirrer
bar and a reflux condenser. Styrene (78 µL, 71 mg, 0.68 mmol) and
‘‘Grubbs-II catalyst’’ (29 mg, 34 µmol) was added and the mixture
heated to 40 °C. The reaction was incomplete (as judged by TLC)
after 22 h; however, neither addition of styrene (311 µL, 282 mg,
2.71 mmol) nor catalyst (13 mg, 15 µmol) changed the product dis-
tribution. After 2 d, the volatiles were removed under reduced
pressure, the residue subjected first to flash-column chromatogra-
phy on silica gel (petroleum ether/ethyl acetate, 95:5) and then
MPLC (petroleum ether/ethyl acetate, 95:5). Yield of 11: 102 mg
(0.15 mmol, 45%). Softening range 52Ϫ70 °C. [α]2D0 ϭ Ϫ41 (c ϭ
0.98, CHCl3). IR (KBr): ν˜ ϭ 3070, 3040, 3010, 2960, 2920, 2880,
2810, 1730, 1630, 1590, 1570, 1480, 1435, 1360, 1310, 1265, 1220,
1190, 1120, 1060 cmϪ1. MS (FAB, NBA ϩ NaI): m/z (%) ϭ 689
(61) [M ϩ Na]ϩ, 197 (100) [CPh2OMe]ϩ. 1H NMR (500 MHz,
CDCl3): δ ϭ 1.12 (t, J ϭ 7.1 Hz, 3 H, 2ЈЈ-H), 2.07Ϫ2.16 (m, 3 H,
2-H, 3-H), 3.00 (s, 6 H, OCH3), 3.98 (q, J ϭ 7.1 Hz, 2 H, 1ЈЈ-H),
5.34 (s, 2 H, 4Ј-H, 5Ј-H), 5.74 (dd, J ϭ 15.9, J ϭ 7.8 Hz, 1 H, 4-
H), 6.06 (dd, J ϭ 15.9, J ϭ 0.5 Hz, 1 H, 5-H), 7.13Ϫ7.34 (m, 25
H, arom. CH) ppm. 13C NMR (125 MHz, CDCl3): δ ϭ 14.2
(OCH2CH3), 24.6 (C-3), 34.5 (C-2), 51.8 (OCH3), 60.1
(OCH2CH3), 77.9 (C-4Ј, C-5Ј), 83.3 (CPh2OMe), 126.0, 126.5,
127.3, 127.4, 127.6, 127.8, 128.2, 128.4, 129.7 (arom. CH), 129.2
(C-5), 129.2 (C-4), 137.9, 141.1, 141.1 (arom. Cipso), 172.8 (C-1)
ppm. C43H43BO6 (666.61): calcd. C 77.48, H 6.50; found C 77.29,
H 6.52.
ϭ 455 K): m/z (%) ϭ 508 (57) [M]ϩ. 1H NMR (500 MHz,
ple
CDCl3): δ ϭ 2.14 (d, J ϭ 3.6 Hz, 1 H, OH), 5.37 (ddd, J ϭ 5.0,
J ϭ 3.6, J ϭ 1.6 Hz, 1 H, 1-H), 6.14 (dd, J ϭ 18.0, J ϭ 1.6 Hz, 1
H, 3-H), 7.16 (dd, J ϭ 18.0, J ϭ 5.0 Hz, 1 H, 2-H), 7.02Ϫ7.42 (m,
25 H, arom. CH) ppm. 13C NMR (125 MHz, CDCl3): δ ϭ 76.1 (C-
1), 96.0 (CPh2), 116.8 (C-3), 126.6, 126.9, 126.9, 127.2, 128.0, 128.5,
128.5, 128.7 (arom. CH), 141.8, 142.4, 142.5 (arom. Cipso), 155.5
(C-2) ppm. C35H29BO3 (508.41): calcd. C 82.68, H 5.75; found C
82.44, H 5.85.
Allylboronic Ester 14: Allyl alcohol 13 (85 mg, 0.17 mmol), triethyl
orthoacetate (190 mg, 1.17 mmol) and propionic acid (1 mg, 1 µL,
10 µmol) were placed in a flask equipped with a magnetic stirrer
bar and a Claisen condenser. The mixture was stirred at 135 °C for
3 h. After cooling to room temperature, the residue was co-distilled
several times with CH2Cl2 to remove the orthoester and propionic
acid. After flash-column chromatography on silica gel (petroleum
ether/ethyl acetate, 90:10) the slightly impure product was obtained.
Yield of 14: 76 mg (0.13 mmol, 79%), colorless foam. An analytical
sample was further purified by means of MPLC (petroleum ether/
ethyl acetate, 98:2); yield: 46 mg (80 µmol, 48%). Softening range
38Ϫ62 °C. [α]2D0 ϭ Ϫ19 (c ϭ 0.72, CHCl3). IR (KBr): ν˜ ϭ 3070,
3040, 3000, 2960, 2910, 2880, 1725, 1630, 1590, 1570, 1480, 1435;
1410, 1355, 1320, 1295, 1270, 1250, 1205, 1165, 1080, 1065, 1015
cmϪ1. MS (EI, 70 eV: Tsource ϭ 420 K, Tsample ϭ 420 K): m/z (%) ϭ
578 (28) [M]ϩ, 533 (4) [M Ϫ OEt]ϩ. 1H NMR (500 MHz, CDCl3):
δ ϭ 1.24 (t, J ϭ 7.1 Hz, 3 H, 2ЈЈ-H), 2.74Ϫ2.84 (m, 1 H, 2-Ha),
2.92Ϫ3.01 (m, 2 H, 3-H, 2-Hb), 4.14 (dq, J ϭ 10.8, J ϭ 7.1 Hz, 1
H, 1ЈЈ-Ha), 4.17 (dq, J ϭ 10.8, J ϭ 7.1 Hz, 1 H, 1ЈЈ-Hb), 6.46 (dd,
J ϭ 16.0, J ϭ 7.9 Hz, 1 H, 4-H), 6.59 (d, J ϭ 16.0 Hz, 1 H, 5-H),
6.99Ϫ7.36 (m, 25 H, arom. CH) ppm. 13C NMR (125 MHz,
CDCl3): δ ϭ 14.3 (C-2ЈЈ), 25.1 (C-3), 35.1 (C-2), 60.5 (C-1ЈЈ), 96.5
(CPh2), 126.0, 126.8, 126.9, 127.0, 127.1, 127.1, 128.5, 128.5, 128.6
(arom. CH), 129.1 (C-4), 130.4 (C-5), 137.7, 142.2, 142.5 (arom.
Cipso), 173.2 (C-1) ppm. C39H35BO4 (578.50): calcd. C 80.97, H
6.10; found C 80.74, H 6.11.
Alkenylboronic Ester 13: Under dry nitrogen, BH3·SMe2 complex
(100 µL of a 10  solution in dimethyl sulfide, 1.00 mmol) in 1,2-
dimethoxyethane (1 mL; DME) was stirred at room temperature.
After addition of cyclohexene (203 µL, 164 mg, 2.00 mmol) a color-
less precipitate formed within 1 h; alkyne 7 (246 mg, 1.00 mmol)
was then added. Stirring was continued until a clear solution
formed. First, trimethylamine N-oxide dihydrate[62Ϫ64](222 mg,
2.00 mmol; water was removed prior to addition by DeanϪStark-
distillation with toluene) was added and then, after 1 h, benzpina-
col (440 mg, 1.20 mmol). The reaction mixture was refluxed for 8 h
until no further consumption (as judged by TLC) of diol was de-
tected. The solvent was then removed under reduced pressure and
the crude product subjected to flash-column chromatography on
silica gel (petroleum ether/ethyl acetate, 98:2) and MPLC (petro-
leum ether/ethyl acetate, 99:1). Yield of 12: 168 mg (0.27 mmol,
27%), colorless foam. Softening range 45Ϫ57 °C. [α]2D0 ϭ ϩ29 (c ϭ
1.16, CHCl3). IR (KBr): ν˜ ϭ 3420, 3070, 3040, 3005, 2935, 2905,
2860, 2840, 1625, 1590, 1570, 1480, 1460, 1450, 1435, 1385, 1355, Ethyl (Z,5R,6S)-6-Hydroxy-5,6-diphenylhex-3-enoate (15): Allylbo-
1330, 1270, 1240, 1210, 1160, 1100 cmϪ1. MS (FAB, NBA ϩ NaI): ronic ester 10 (152 mg, 0.23 mmol) was dissolved in CH2Cl2 (114
Eur. J. Org. Chem. 2004, 5011Ϫ5019
www.eurjoc.org
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
5015

J. Pietruszka, N. Schöne
FULL PAPER
µL) in a Schlenk flask equipped with stirrer bar and septum. Ben-
zaldehyde (29 mg, 28 µL, 0.27 mmol) was added at 0 °C and the
removed under reduced pressure. The spectroscopic data of the
crude product (quant. conversion) are in good agreement with
mixture warmed to room temperature overnight. After complete those previously published.[57] 1H NMR (500 MHz, CDCl3): δ ϭ
consumption of reagent 10 (as judged by TLC), the solvents were
removed under reduced pressure and the crude product subjected
to thorough flash-column chromatography and MPLC (petroleum
ether/ethyl acetate, 85:15) to furnish the pure product. Yield of 15:
46 mg (0.15 mmol, 65%, Ͼ 99% ee), colorless oil. [α]2D0 ϭ Ϫ97 (c ϭ
0.54, CHCl3; Ͼ 99% ee). HPLC (CHIRALCEL OD, hexane/iP-
rOH, 95:5): tR ϭ 12.00 min. IR (neat): ν˜ ϭ 3477, 3090, 3060, 3030,
2980, 2935, 2905, 2870, 1734, 1600, 1585, 1495, 1450, 1400, 1370,
1325, 1300, 1260, 1175, 1095, 1030 cmϪ1. MS (EI, 70 eV: Tsource ϭ
390 K, Tsample ϭ 360 K): m/z (%) ϭ 310 (0.3) [M]ϩ, 292 (0.1) [M
Ϫ H2O]ϩ, 265 (1) [M Ϫ OEt]ϩ, 247 (1) [M Ϫ (H2O ϩ EtO)] ϩ, 204
(95) [M Ϫ PhCHO]ϩ, 130 (100) [C10H10]ϩ. 1H NMR (500 MHz,
CDCl3): δ ϭ 1.22 (t, J ϭ 7.1 Hz, 3 H, 2Ј-H), 2.63 (d, J ϭ 3.1 Hz,
1 H, OH), 2.98 (ddd, J ϭ 17.0, J ϭ 6.9, J ϭ 1.6 Hz, 1 H, 2-Ha),
3.08 (ddd, J ϭ 17.0, J ϭ 7.7, J ϭ 1.7 Hz, 1 H, 2-Hb), 3.80 (ddd,
J ϭ 10.2, J ϭ 7.3, J ϭ 1.0 Hz, 1 H, 5-H), 4.09 (q, J ϭ 7.1 Hz, 2
H, 1Ј-H), 4.84 (dd, J ϭ 7.3, J ϭ 3.1 Hz, 1 H, 6-H), 5.83 (dddd,
J ϭ 10.8, J ϭ 7.7, J ϭ 6.9, J ϭ 1.0 Hz, 1 H, 3-H), 6.11 (dddd, J ϭ
10.8, J ϭ 10.2, J ϭ 1.7, J ϭ 1.6 Hz, 1 H, 4-H), 7.06Ϫ7.22 (m, 10
H, arom. CH) ppm. 13C NMR (125 MHz, CDCl3): δ ϭ 14.1 (C-
2Ј), 33.1 (C-2), 52.7 (C-5), 60.8 (C-1Ј), 77.9 (C-6), 124.3 (C-3),
126.5, 126.6, 127.4, 127.9, 128.3, 128.4 (arom. CH), 132.3 (C-4),
140.7, 142.0 (arom. Cipso), 171.6 (C-1) ppm. C20H22O3 (310.39):
calcd. C 77.39, H 7.14; found C 77.32, H 7.20. According to the
same procedure, homoallyl alcohol ent-15 (75 mg, 0.24 mmol, 78%,
Ͼ 99% ee) was obtained from allylboronic ester 11 (206 mg,
0.31 mmol). [α]2D0 ϭ ϩ98 (c ϭ 1.16, CHCl3; Ͼ 99% ee). HPLC
(CHIRALCEL OD, hexane/iPrOH, 95:5): tR ϭ 7.78 min. Starting
with reagent 14 (40 mg, 69 µmol), alcohol 15 (18 mg, 58 µmol, 84%,
ee ϭ 91%) was isolated.
3.13 (ddd, J ϭ 10.8, J ϭ 9.7, J ϭ 4.6 Hz, 1 H, 5-H), 4.27 (dd, J ϭ
11.4, J ϭ 4.6 Hz, 1 H, 6-Ha), 4.41 (dd, J ϭ 11.4, J ϭ 10.8 Hz, 1
H, 6-Hb), 5.30 (d, J ϭ 9.7 Hz, 1 H, 4-H), 7.04Ϫ7.91 (m, 15 H,
arom CH) ppm. 13C NMR (125 MHz, CDCl3): δ ϭ 51.3 (C-5),
66.3 (C-6), 78.8 (C-4), 126.4, 127.4, 127.6, 127.6, 128.0, 128.5,
128.7, 130.9, 134.1, 137.4, 140.9 (arom. CH, arom. Cipso) ppm.
Allylboronic Esters 19 and 20: Under dry nitrogen alcohol, 18
(100 mg, 1.43 mmol) was dissolved in CH2Cl2 (1.1 mL) and imidaz-
ole (107 mg, 1.57 mmol) was added at 0 °C. After addition of tert-
butyldimethylsilyl chloride (215 mg, 1.43 mmol; TBSCl), the mix-
ture was stirred at room temperature for 5 h. Hydrolysis with water
(1.5 mL) was followed by extraction with pentane (3 ϫ 5 mL). The
combined organic layers were washed with brine, dried with
MgSO4, filtered and the solvents removed under reduced pressure.
The crude product was purified by flash-column chromatography
(pentane/Et2O, 98:2); the spectroscopic data are in full agreement
with those previously reported.[61] Yield: 223 mg (1.21 mmol, 85%),
colorless oil. Starting from ent-18 (100 mg, 1.43 mmol), 208 mg
(1.13 mmol, 79%) of a colorless oil was obtained. Under dry nitro-
gen BH3·SMe2 complex (100 µL of a 10  solution in dimethyl
sulfide, 1.00 mmol) in 1,2-dimethoxyethane (1 mL; DME) was
stirred at room temperature. After addition of cyclohexene (203 µL,
164 mg, 2.00 mmol) a colorless precipitate formed within 1 h; the
silyl-protected alkyne (184 mg, 1.00 mmol) was then added. Stirring
was continued until a clear solution formed. Next, trimethylamine
N-oxide dihydrate[62Ϫ64] (222 mg, 2.00 mmol; water was removed
prior to addition by DeanϪStark-distillation with toluene) was ad-
ded and after 1 h the ‘‘diol’’ (455 mg, 1.00 mmol) was added. The
reaction mixture was stirred until no further consumption (as
judged by TLC) of diol was detected. The solvent was removed
under reduced pressure and the crude product subjected to flash-
column chromatography on silica gel (petroleum ether/ethyl acet-
ate, 98:2 to 90:10). An analytical sample was purified by MPLC
(petroleum ether/ethyl acetate, 99:1). (3E,2S,4ЈR,5ЈR)-(tert-Butyldi-
methylsilyl) 4-[4Ј,5Ј-bis(methoxydiphenylmethyl)-1Ј,3Ј,2Ј-dioxaboro-
(1S,2S)-1,2-Diphenylpropane-1,3-diol (16): Homoallyl alcohol 15
(26 mg, 84 µmol) was first dissolved in CH2Cl2 (10 mL). Ozone was
then bubbled through the solution at Ϫ78 °C until a blue color
persisted. Excess ozone was removed by passing a continuous
stream of oxygen through the solution. After reductive work up
with Me2S (1 mL), the mixture was warmed to room temperature
and the volatiles removed under reduced pressure. The residue was
dissolved in THF (10 mL) and LiAlH4 (100 mg, 2.64 mmol) was
added. After 1 h, the mixture was diluted with Et2O (5 mL) and
treated successively with H2O (250 µL), 2  aqueous NaOH (500
µL) and H2O (500 µL). The solids were filtered off, washed thor-
oughly and the filtrate dried with sodium sulfate. Filtration and
removal of the solvents under reduced pressure furnished the prod-
uct. After MPLC (petroleum ether/ethyl acetate, 60:40) a spectro-
scopically pure product was obtained. Yield of 16: 11 mg (48 µmol,
57%), colorless solid, spectroscopic data were in good agreement
with those previously reported.[57] [α]2D0 ϭ ϩ92 (c ϭ 0.55, CHCl3);
ϩ67 (c ϭ 0.55, acetone) [ref.[57] for ent-16: Ϫ64 (c ϭ 0.90, acetone)].
1H NMR (500 MHz, CDCl3): δ ϭ 2.95 (br. s, 2 H, OH), 3.16 (ddd,
J ϭ 8.8, J ϭ 7.7, J ϭ 4.5 Hz, 1 H, 2-H), 3.97 (dd, J ϭ 11.1, J ϭ
4.5 Hz, 1 H, 3-Ha), 4.20 (dd, J ϭ 11.1, J ϭ 7.7 Hz, 1 H, 3-Hb),
5.03 (d, J ϭ 8.8 Hz, 1 H, 1-H), 7.01Ϫ7.53 (m, 10 H, arom. CH)
ppm. 13C NMR (125 MHz, CDCl3): δ ϭ 54.9 (C-2), 66.3 (C-3),
79.6 (C-1), 126.5, 126.9, 127.7, 128.1, 128.4, 128.5 (arom. CH),
139.2, 142.7 (arom. Cipso) ppm.
lan-2Ј-yl]but-3-en-2-yl Ether: Softening range 57Ϫ69 °C. [α]2D0
ϭ
Ϫ48 (c ϭ 1.08, CHCl3). IR (KBr): ν˜ ϭ 3070, 3040, 3010, 2940,
2910, 2880, 2840, 2810, 1630, 1590, 1570, 1480, 1460, 1450, 1435,
1390, 1370, 1360, 1330, 1270, 1240, 1220, 1170, 1130, 1060, 1020,
1000 cmϪ1. MS (FAB, NBA ϩ NaI): m/z (%) ϭ 671 (7) [M ϩ
1
Na]ϩ, 197 (100) [CPh2OMe]ϩ. H NMR (500 MHz, CDCl3): δ ϭ
Ϫ0.04, Ϫ0.03 [2 s, 6 H, Si(CH3)2], 0.83 [s, 9 H, C(CH3)3], 1.07 (d,
3J1,2 ϭ 6.4 Hz, 3 H, 1-H), 3.00 (s, 6 H, OCH3), 4.13 (qdd, J ϭ 6.4,
J ϭ 4.6, J ϭ 1.6 Hz, 1 H, 2-H), 5.21 (dd, J ϭ 17.9, J ϭ 1.6 Hz, 1
H, 4-H), 5.35 (s, 2 H, 4Ј-H, 5Ј-H), 6.17 (dd, J ϭ 17.9, J ϭ 4.6 Hz,
1 H, 3-H), 7.22Ϫ7.37 (m, 20 H, arom. CH) ppm. 13C NMR
(125 MHz, CDCl3): δ ϭ Ϫ5.0, Ϫ4.7 [Si(CH3)2], 18.3 [C(CH3)3],
23.8 (C-1), 25.9 [C(CH3)3], 51.8 (OCH3), 70.0 (C-2), 77.6 (C-4Ј, C-
5Ј), 83.4 (CPh2OMe), 114.5 (C-4), 127.2, 127.2, 127.5, 127.8, 128.5,
129.7 (arom. CH), 141.1, 141.4 (arom. Cipso), 156.5 (C-3) ppm.
C40H49BO5Si (648.71): calcd. C 74.06, H 7.61; found C 73.95, H
7.62. The (3E,2R,4ЈR,5ЈR) diastereoisomer was obtained starting
from the corresponding silyl ether (188 mg, 1.02 mmol) and ‘‘diol’’
(464 mg, 1.02 mmol). (3E,2R,4ЈR,5ЈR)-(tert-Butyldimethylsilyl) 4-
[4Ј,5Ј-bis(methoxydiphenylmethyl)-1Ј,3Ј,2Ј-dioxaborolan-2Ј-yl]but-3-
en-2-yl Ether: Softening range 58Ϫ68 °C. [α]2D0 ϭ Ϫ58 (c ϭ 1.10,
(4S,5S)-2,4,5-Triphenyl-1,3,2-dioxaborinane (17): Diol 16 (11 mg, CHCl3). IR (KBr): ν˜ ϭ 3070, 3040, 3010, 2940, 2920, 2880, 2840,
48 µmol) and phenylboronic acid (7 mg, 53 µmol) were dissolved
in CH2Cl2 (526 µL) and two spheres of molecular sieves (4 A) were
added. The mixture was stirred overnight, filtered and the solvent
2810, 1630, 1590, 1570, 1480, 1460, 1450, 1435, 1390, 1370, 1360,
1330, 1270, 1240, 1225, 1165, 1130, 1060, 1020, 1000 cmϪ1. MS
(CI, NH3: Tsource ϭ 395 K, Tsample ϭ 475 K): m/z (%) ϭ 666 (7) [M
˚
5016
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
Eur. J. Org. Chem. 2004, 5011Ϫ5019

New 1,3-Disubstituted Enantiomerically Pure Allylboronic Esters
FULL PAPER
ϩ NH4]ϩ, 197 (100) [CPh2OMe]ϩ. 1H NMR (500 MHz, CDCl3):
δ ϭ Ϫ0.03, Ϫ0.03 [2 s, 6 H, Si(CH3)2], 0.85 [s, 9 H, C(CH3)3], 1.07
(d, J ϭ 6.5 Hz, 3 H, 1-H), 2.99 (s, 6 H, OCH3), 4.14 (qdd, J ϭ 6.5,
J ϭ 4.7, J ϭ 1.5 Hz, 1 H, 2-H), 5.17 (dd, J ϭ 17.9, J ϭ 1.5 Hz, 1
H, 4-H), 5.33 (s, 2 H, 4Ј-H, 5Ј-H), 6.16 (dd, J ϭ 17.9, J ϭ 4.7 Hz,
1 H, 3-H), 7.23Ϫ7.37 (m, 20 H, arom. CH) ppm. 13C NMR
(125 MHz, CDCl3): δ ϭ Ϫ5.0, Ϫ4.7 [Si(CH3)2], 18.3 [C(CH3)3],
23.8 (C-1), 25.9 [C(CH3)3], 51.8, 51.8 (OCH3), 70.2 (C-2), 77.7 (C-
4Ј, C-5Ј), 83.4 (CPh2OMe), 114.6 (C-4), 127.2, 127.2, 127.4, 127.8,
128.5, 129.7 (arom. CH), 141.1, 141.5 (arom. Cipso), 156.5 (C-3)
ppm. C40H49BO5Si (648.71): calcd. C 74.06, H 7.61; found C 73.93,
H 7.57. The silyl ether was deprotected by dissolving the crude
alkenylboronic ester (531 mg) in a minimum amount of CH2Cl2
and ethanol (7.64 mL). Concentrated hydrochloric acid (159 µL,
1.92 mmol) in ethanol (1.43 mL) was then added dropwise. After
1 h, complete consumption (as judged by TLC) of the starting ma-
terial was detected. Saturated aqueous sodium hydrogencarbonate
(637 µL) was added and the volume of the solvent reduced under
reduced pressure. Water was then added and the aqueous layer ex-
tracted with Et2O (3 ϫ 20 mL). The combined organic layers were
washed with saturated brine, dried with MgSO4 and subjected to
flash-column chromatography on silica gel (petroleum ether/ethyl
acetate, 85:15) to furnish the spectroscopically pure product. Yield
(over 2 steps): 298 mg (0.56 mmol, 56%), colorless foam. An ana-
lytical sample was further purified by MPLC (petroleum ether/ethyl
acetate, 85:15). (3E,2S,4ЈR,5ЈR)-4-[4Ј,5Ј-Bis(methoxydiphenylmeth-
yl)-1Ј,3Ј,2Ј-dioxaborolan-2Ј-yl]but-3-en-2-ol: Softening range 80Ϫ95
°C. [α]2D0 ϭ Ϫ74 (c ϭ 1.02, CHCl3). IR (KBr): ν˜ ϭ 3560, 3400,
3070, 3040, 3010, 2950, 2920, 2880, 2815, 1635, 1590, 1570, 1480,
1435, 1390, 1360, 1340, 1310, 1270, 1225, 1170, 1140, 1060, 1020,
1000 cmϪ1. MS (FAB, NBA ϩ NaI): m/z (%) ϭ 557 (18) [M ϩ
column chromatography on silica gel (petroleum ether/ethyl acet-
ate, 95:5) the spectroscopically pure product was obtained. Yield
of 19: 244 mg (0.40 mmol, 78%), colorless foam. An analytically
pure sample was obtained after MPLC (petroleum ether/ethyl acet-
ate, 98:2). 19: Softening range 41Ϫ57 °C. [α]2D0 ϭ Ϫ86 (c ϭ 1.15,
CHCl3). IR (KBr): ν˜ ϭ 3070, 3040, 3005, 2960, 2920, 2890, 2810,
1730, 1590, 1570, 1480, 1435, 1370, 1360, 1340, 1305, 1260, 1215,
1190, 1160, 1120, 1070, 1060, 1015, 1000 cmϪ1. MS (FAB, NBA ϩ
1
NaI): m/z (%) ϭ 627 (3) [M ϩ Na]ϩ, 197 (100) [CPh2OMe]ϩ. H
NMR (500 MHz, CDCl3): δ ϭ 1.12 (t, J ϭ 7.1 Hz, 3 H, 2ЈЈ-H),
1.50 (m, 3 H, 6-H), 1.84 (m, 1 H, 3-H), 1.94 (dd, J ϭ 15.4, J ϭ
10.7 Hz, 1 H, 2-Ha), 2.07 (dd, J ϭ 15.4, J ϭ 4.5 Hz, 1 H, 2-Hb),
2.99 (s, 6 H, OCH3), 3.92 (dq, J ϭ 10.8, J ϭ 7.1 Hz, 1 H, 1ЈЈ-Ha),
3.94 (dq, J ϭ 10.8, J ϭ 7.1 Hz, 1 H, 1ЈЈ-Hb), 5.11 (m, 2 H, 4-H, 5-
H), 5.29 (s, 2 H, 4Ј-H, 5Ј-H), 7.25Ϫ7.34 (m, 20 H, arom. CH) ppm.
13C NMR (125 MHz, CDCl3): δ ϭ 14.2 (C-2ЈЈ), 18.0 (C-6), 23.9
(C-3), 34.3 (C-2), 51.7, 51.7 (OCH3), 59.9 (C-1ЈЈ), 77.9 (C-4Ј, C-
5Ј), 83.3 (CPh2OMe), 123.8 (C-5), 127.3, 127.3, 127.5, 127.8, 128.4,
129.7 (arom. CH), 129.6 (C-4), 141.1, 141.2 (arom. Cipso), 173.2 (C-
1). C38H41BO6 (604.54): calcd. C 75.50, H 6.84; found C 75.36, H
6.86. The spectroscopically pure diastereoisomer 20 was formed in
80% yield (231 mg, 0.38 mmol) after Johnson rearrangement of the
appropriate allyl alcohol (255 mg, 0.48 mmol). An analytically pure
sample was obtained after MPLC (petroleum ether/ethyl acetate,
98:2). Recrystallization from pentane/ethanol yielded crystals suit-
able for X-ray structural analysis. 20: M.p. 150Ϫ152 °C. [α]2D0
ϭ
Ϫ98 (c ϭ 1.30, CHCl3). IR (KBr): ν˜ ϭ 3070, 3040, 3005, 2960,
2940, 2920, 2890, 2835, 2810, 1730, 1590, 1570, 1480, 1435, 1370,
1360, 1345, 1325, 1305, 1270, 1220, 1195, 1165, 1125, 1070, 1060,
1020, 1000 cmϪ1. MS (FAB, NBA ϩ NaI): m/z (%) ϭ 627 (50)
[M ϩ Na]ϩ, 197 (100) [CPh2OMe]ϩ. 1H NMR (500 MHz, CDCl3):
δ ϭ 1.14 (t, J ϭ 7.1 Hz, 3 H, 2ЈЈ-H), 1.50 (m, 3 H, 6-H), 1.86 (m,
1 H, 3-H), 2.00 (d, J ϭ 9.1 Hz, 1 H, 2-Ha), 2.00 (d, J ϭ 6.1 Hz, 1
H, 2-Hb), 2.99 (s, 6 H, OCH3), 4.04 (dq, J ϭ 10.8, J ϭ 7.1 Hz, 1
H, 1ЈЈ-Ha), 4.06 (dq, J ϭ 10.8, J ϭ 7.1 Hz, 1 H, 1ЈЈ-Hb), 4.98 (ddq,
J ϭ 15.3, J ϭ 7.9, J ϭ 1.5 Hz, 1 H, 4-H), 5.09 (dqd, J ϭ 15.3, J ϭ
6.3, J ϭ 1.0 Hz, 1 H, 5-H), 5.30 (s, 2 H, 4Ј-H, 5Ј-H), 7.23Ϫ7.34
(m, 20 H, arom. CH) ppm. 13C NMR (125 MHz, CDCl3): δ ϭ 14.2
(C-2ЈЈ), 17.9 (C-6), 24.1 (C-3), 34.7 (C-2), 51.8 (OCH3), 59.9 (C-
1ЈЈ), 77.9 (C-4Ј, C-5Ј), 83.4 (CPh2OMe), 124.2 (C-5), 127.2, 127.3,
127.5, 127.8, 128.5, 129.7 (arom. CH), 129.2 (C-4), 141.2, 141.3
(arom. Cipso), 173.1 (C-1) ppm. C38H41BO6 (604.54): calcd. C 75.50,
H 6.84; found C 75.44, H 6.86.
1
Na]ϩ, 197 (100) [CPh2OMe]ϩ. H NMR (500 MHz, CDCl3): δ ϭ
1.13 (d, J ϭ 6.5 Hz, 3 H, 1-H), 1.50 (br. s, 1 H, OH), 3.00 (s, 6 H,
OCH3), 4.14 (qdd, J ϭ 6.5, J ϭ 5.0, J ϭ 1.5 Hz, 1 H, 2-H), 5.20
(dd, J ϭ 18.1, J ϭ 1.5 Hz, 1 H, 4-H), 5.35 (s, 2 H, 4Ј-H, 5Ј-H),
6.21 (dd, J ϭ 18.1, J ϭ 5.0 Hz, 1 H, 3-H), 7.23Ϫ7.36 (m, 20 H,
arom. CH) ppm. 13C NMR (125 MHz, CDCl3): δ ϭ 22.7 (C-1),
51.8, 51.8 (OCH3), 69.4 (C-2), 77.7 (C-4Ј, C-5Ј), 83.3 (CPh2OMe),
115.4 (C-4), 127.2, 127.3, 127.5, 127.8, 128.5, 129.7 (arom. CH),
141.0, 141.3 (arom. Cipso), 155.7 (C-3). C34H35BO5 (534.45): calcd.
C 76.41, H 6.60; found C 76.30, H 6.65. The (3E,2R,4ЈR,5ЈR) dia-
stereoisomer was obtained in the same way in 50% yield (274 mg,
0.51 mmol) over two steps. (3E,2S,4ЈR,5ЈR)-4-[4Ј,5Ј-Bis(methoxydi-
phenylmethyl)-1Ј,3Ј,2Ј-dioxaborolan-2Ј-yl]but-3-en-2-ol: Softening
range 81Ϫ91 °C. [α]2D0 ϭ Ϫ80 (c ϭ 1.25, CHCl3). IR (KBr): ν˜ ϭ
Ethyl (3Z,5S,6S)-6-Hydroxy-5-methyl-6-phenylhex-3-enoate (21):
3560, 3410, 3070, 3040, 3010, 2950, 2920, 2880, 2810, 1635, 1590, Allylboronic ester 19 (341 mg, 0.56 mmol) was dissolved in CH2Cl2
1570, 1480, 1450, 1435, 1390, 1360, 1340, 1315, 1270, 1225, 1170,
(282 µL) in a Schlenk flask equipped with a stirrer bar and septum.
1140, 1060, 1020, 1000 cmϪ1. MS (FAB, NBA ϩ NaI): m/z (%) ϭ Benzaldehyde (69 µL, 72 mg, 0.68 mmol) was added at 0 °C and the
557 (37) [M ϩ Na]ϩ, 197 (100) [CPh2OMe]ϩ. 1H NMR (500 MHz, mixture warmed to room temperature overnight. After complete
CDCl3): δ ϭ 1.13 (d, J ϭ 6.5 Hz, 3 H, 1-H), 1.43 (br, 1 H, OH),
3.00 (s, 6 H, OCH3), 4.15 (qdd, J ϭ 6.5, J ϭ 4.9, J ϭ 1.5 Hz, 1 H, removed under reduced pressure and the crude product subjected
2-H), 5.20 (dd, J4,3 ϭ 18.1, J ϭ 1.5 Hz, 1 H, 4-H), 5.35 (s, 2 H, 4Ј- to thorough flash-column chromatography (petroleum ether/ethyl
H, 5Ј-H), 6.22 (dd, J ϭ 18.1, J ϭ 4.9 Hz, 1 H, 3-H), 7.23Ϫ7.36 (m, acetate, 95:5 to 85:15) to furnish a slightly impure product. Yield
20 H, arom. CH) ppm. 13C NMR (125 MHz, CDCl3): δ ϭ 22.6 (C-
of 21: 133 mg (0.54 mmol, 95%, Ͼ 97% ee), colorless oil. An ana-
consumption of reagent 19 (as judged by TLC) the solvents were
1), 51.8 (OCH3), 69.4 (C-2), 77.7 (C-4Ј, C-5Ј), 83.4 (CPh2OMe), lytically pure sample was obtained after purification by means of
115.3 (C-4), 127.2, 127.3, 127.5, 127.8, 128.5, 129.7 (arom. CH), MPLC (petroleum ether/ethyl acetate, 85:15). 21: [α]2D0 ϭ Ϫ130 (c ϭ
141.1, 141.3 (arom. Cipso), 155.7 (C-3) ppm. C34H35BO5 (534.45): 1.55, CHCl3, Ͼ 97% ee). HPLC (CHIRALCEL OD, hexane/iP-
calcd. C 76.41, H 6.60; found C 75.62, H 6.53. The above-formed
rOH, 98:2): tR ϭ 9.73 min (no baseline separation). IR (film): ν˜ ϭ
allyl alcohol (277 mg, 0.52 mmol), triethyl orthoacetate (376 mg, 3460, 3070, 3040, 3005, 2955, 2905, 2880, 2850, 1730, 1590, 1575,
2.32 mmol) and propionic acid (1.5 mg, 1.5 µL, 0.02 mmol) were
added to a flask equipped with a magnetic stirrer bar and a Claisen
condenser. The mixture was stirred at 135 °C for 3 h. After cooling
1480, 1440, 1390, 1360, 1315, 1240, 1160, 1080, 1020 cmϪ1. MS
(EI, 70 eV: Tsource ϭ 400 K, Tsample ϭ 315 K): m/z (%) ϭ 248 (2)
[M]ϩ, 230 (0.1) [M Ϫ H2O]ϩ, 203 (1) [M Ϫ OEt]ϩ, 185 (2) [M Ϫ
1
to room temperature, the residue was co-distilled several times with (H2O ϩ EtO)]ϩ, 142 (100) [M Ϫ PhCHO]ϩ. H NMR (500 MHz,
CH2Cl2 to remove the orthoester and propionic acid. After flash-
CDCl3): δ ϭ 0.81 (d, J ϭ 6.7 Hz, 3 H, CH3), 1.26 (t, J ϭ 7.1 Hz,
Eur. J. Org. Chem. 2004, 5011Ϫ5019
www.eurjoc.org
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
5017

J. Pietruszka, N. Schöne
FULL PAPER
3 H, 2Ј-H), 2.64 (d, J ϭ 2.1 Hz, 1 H, OH), 2.71 (ddqd, J ϭ 10.1,
J ϭ 8.1, J ϭ 6.7, J ϭ 1.0 Hz, 1 H, 5-H), 3.08 (ddd, J ϭ 16.7, J ϭ
7.2, J ϭ 1.5 Hz, 1 H, 2-Ha), 3.13 (ddd, J ϭ 16.7, J ϭ 7.6, J ϭ
1.6 Hz, 1 H, 2-Hb), 4.15 (q, J ϭ 7.1 Hz, 2 H, 1Ј-H), 4.32 (dd, J ϭ
8.1, J ϭ 2.1 Hz, 1 H, 6-H), 5.55 (dddd, J ϭ 10.8, J ϭ 10.1, J ϭ
1.6, J ϭ 1.5 Hz, 1 H, 4-H), 5.73 (dddd, J ϭ 10.8, J ϭ 7.6, J ϭ 7.2,
J ϭ 1.0 Hz, 1 H, 3-H), 7.25Ϫ7.34 (m, 5 H, arom. CH) ppm. 13C
NMR (125 MHz, CDCl3): δ ϭ 14.1 (C-2Ј), 17.1 (CH3), 33.2 (C-2),
40.6 (C-5), 60.8 (C-1Ј), 78.4 (C-6), 123.2 (C-3), 126.9, 127.6, 128.2
(arom. CH), 135.9 (C-4), 142.5 (arom. Cipso), 171.9 (C-1) ppm.
C15H20O3 (248.32): calcd. C 72.55, H 8.12; found C 72.47, H 8.07.
According to the same procedure, homoallyl alcohol ent-21 (58 mg,
0.23 mmol, 90%, Ͼ 97% ee) was obtained from allylboronic ester
20 (157 mg, 0.26 mmol). [α]2D0 ϭ ϩ137 (c ϭ 0.88, CHCl3, Ͼ 97%
Acknowledgments
We gratefully acknowledge the Deutsche Forschungsgemeinschaft,
the Fonds der Chemischen Industrie, the Otto-Röhm-Gedächtnis-
stiftung and the Landesgraduiertenförderung Baden Württemberg
(‘‘Graduiertenstipendium’’ for N. S.) for their generous support of
our projects. Donations from the Boehringer Ingelheim KG, the
Degussa AG, the Bayer AG, the BASF AG, the Wacker AG and
Novartis AG are greatly appreciated. We thank Dr. Wolfgang Frey
for performing the X-ray structure analysis.
[1]
S. E. Denmark, N. G. Almstead, in Modern Carbonyl Chemis-
try (Ed.: J. Otera), Wiley-VCH, Weinheim, 2000, pp. 299Ϫ401.
S. R. Chemler, W. R. Roush, in Modern Carbonyl Chemistry
[2]
ee). HPLC (CHIRALCEL OD, hexane/iPrOH, 98:2): tR
ϭ
9.11 min (no baseline separation).
(Ed.: J. Otera), Wiley-VCH, Weinheim, 2000, pp. 403Ϫ490.
W. R. Roush, in Methoden der Organischen Chemie (Houben-
[3]
Weyl), vol. 3, E 21 (‘‘Stereoselective Synthesis’’) (Eds.: G.
Helmchen, R. W. Hoffmann, J. Mulzer, E. Schaumann), Thi-
eme Verlag, Stuttgart, 1996, pp. 1410Ϫ1486.
(1S,2S)-2-Methyl-1-phenylpropane-1,3-diol (22): Homoallyl alcohol
21 (39 mg, 0.16 mmol) was first dissolved in CH2Cl2 (10 mL).
Ozone was then bubbled through the solution at Ϫ78 °C until a
blue color persisted. Excess ozone was removed by passing a con-
tinuous stream of oxygen through the solution. After reductive
work up with Me2S (1 mL), the mixture was warmed to room tem-
perature and the volatiles removed under reduced pressure. The
residue was dissolved in Et2O (5 mL) and LiAlH4 (60 mg,
1.57 mmol) was added. After 1 h, the mixture was diluted with
Et2O (5 mL) and treated successively with H2O (100 µL), 2  aque-
ous NaOH (200 µL) and H2O (200 µL). The solids were filtered
off, washed thoroughly and the filtrate dried with sodium sulfate.
Filtration and removal of the solvents under reduced pressure fur-
nished the product. After MPLC (petroleum ether/ethyl acetate,
60:40), a spectroscopically pure product was obtained. Yield of 22:
18 mg (0.11 mmol, 69%, Ͼ 98% ee), colorless oil. The spectroscopic
data are in good agreement with those previously reported.[59][60]
[α]2D0 ϭ Ϫ51 (c ϭ 0.60, CHCl3) [lit.[60] for 22: Ϫ44 (c ϭ 1.04,
CHCl3), ee ϭ 89%]. GLC (Bondex-un-α/β, 100 °C, 1Ј iso, then 2.5
°C·minϪ1): tR ϭ 23.11 min (no complete baseline separation). 1H
NMR (500 MHz, CDCl3): δ ϭ 0.69 (d, J ϭ 7.0 Hz, 3 H, CH3),
2.04 (mc, 1 H, 2-H), 3.10, 3.19 (2 br. s, 2 H, OH), 3.69 (dd, J ϭ
10.8, J ϭ 7.5 Hz, 1 H, 3-Ha), 3.75 (d, J ϭ 10.8 Hz, 1 H, 3-Hb),
4.52 (d, J ϭ 8.4 Hz, 1 H, 1-H), 7.26Ϫ7.37 (m, 5 H, arom. CH)
ppm. 13C NMR (125 MHz, CDCl3): δ ϭ 13.8 (CH3), 41.7 (C-2),
67.9 (C-3), 80.8 (C-1), 126.7, 127.8, 128.4 (arom. CH), 143.4 (arom.
Cipso). According to the same procedure, diol ent-22 (10 mg, 60
µmol, 53%, Ͼ 98% ee) was obtained from homoallyl alcohol ent-
21 (28 mg, 0.11 mmol). [α]2D0 ϭ ϩ50 (c ϭ 0.50, CHCl3, Ͼ 98% ee).
[4]
D. Hoppe, in Methoden der Organischen Chemie (Houben-
Weyl), vol. 3, E 21 (‘‘Stereoselective Synthesis’’) (Eds.: G.
Helmchen, R. W. Hoffmann, J. Mulzer, E. Schaumann), Thi-
eme Verlag, Stuttgart, 1996, pp. 1357Ϫ1409.
[5]
D. S. Matteson, Stereodirected Synthesis with Organoboranes,
Springer-Verlag, Heidelberg, 1995.
[6]
Y. Yamamoto, N. Asao, Chem. Rev. 1993, 93, 2207Ϫ2293.
[7]
R. W. Hoffmann, U. Weidmann, J. Organomet. Chem. 1980,
195, 137Ϫ146.
[8]
H. C. Brown, M. C. Desai, P. K. Jadhav, J. Org. Chem. 1982,
47, 5065Ϫ5069.
M. M. Midland, S. B. Preston, J. Am. Chem. Soc. 1982, 104,
2330.
D. J. S. Tsai, D. S. Matteson, Organometallics 1983, 2,
236Ϫ241.
[9]
[10]
[11]
R. W. Hoffmann, B. Landmann, Angew. Chem. 1984, 96,
427Ϫ428; Angew. Chem. Int. Ed. Engl. 1984, 23, 437Ϫ438.
[12]
E. Moret, M. Schlosser, Tetrahedron Lett. 1984, 25,
4491Ϫ4494.
[13]
H. C. Brown, P. K. Jadhav, K. S. Bhat, J. Am. Chem. Soc. 1985,
107, 2564.
K. Ditrich, T. Bube, R. Stürmer, R. W. Hoffmann, Angew.
Chem. 1986, 98, 1016Ϫ1018; Angew. Chem. Int. Ed. 1986, 25,
1028Ϫ1030.
R. W. Hoffmann, B. Landmann, Chem. Ber. 1986, 119,
2013Ϫ2024.
[14]
[15]
[16]
R. W. Hoffmann, B. Landmann, Chem. Ber. 1986, 119,
1039Ϫ1053.
[17]
R. W. Hoffmann, S. Dresely, Angew. Chem. 1986, 98, 186Ϫ187;
Angew. Chem. Intl. Ed. Engl. 1986, 25, 189Ϫ190.
[18]
R. W. Hoffmann, S. Dresely, Tetrahedron Lett. 1987, 28,
GLC (Bondex-un-α/β, 100 °C, 1Ј iso, then 2.5 °C·minϪ1): tR
ϭ
5303Ϫ5306.
22.89 min (no baseline separation).
[19]
M. Vaultier, F. Truchet, B. Carboni, R. W. Hoffmann, I.
Denne, Tetrahedron Lett. 1987, 28, 4169Ϫ4172.
[20]
R. W. Hoffmann, Pure Appl. Chem. 1988, 60, 123Ϫ130.
(4R,5R)-5-Methyl-2,4-diphenyl-1,3,2-dioxaborinane (23): Diol ent-
22 (8 mg, 48 µmol) and phenylboronic acid (7 mg, 53 µmol) were
dissolved in CH2Cl2 (480 µL) and two spheres of molecular sieves
[21]
R. W. Hoffmann, S. Dresely, J. W. Lanz, Chem. Ber. 1988,
121, 1501Ϫ1507.
R. W. Hoffmann, S. Dresely, Synthesis 1988, 103Ϫ106.
M. W. Andersen, B. Hildebrandt, G. Köster, R. W. Hoffmann,
[22]
[23]
˚
(4 A) were added. The mixture was stirred overnight, filtered and
Chem. Ber. 1989, 122, 1777Ϫ1782.
the solvent removed under reduced pressure. The NMR data of
the crude product (quant. conversion) were obtained. 1H NMR
(500 MHz, CDCl3): δ ϭ 0.84 (d, J ϭ 6.8 Hz, 3 H, CH3), 2.08 (ddqd,
J ϭ 10.3, J ϭ 9.1, J ϭ 6.8, J ϭ 4.4 Hz, 1 H, 5-H), 3.87 (dd, J ϭ
11.2, J ϭ 10.3 Hz, 1 H, 6-Ha), 4.12 (dd, J ϭ 11.2, J ϭ 4.4 Hz, 1
H, 6-Hb), 4.74 (d, J ϭ 9.1 Hz, 1 H, 4-H), 7.31Ϫ7.86 (m, 10 H,
arom. CH) ppm. 13C NMR (125 MHz, CDCl3): δ ϭ 13.3 (CH3),
38.5 (C-5), 67.4 (C-6), 80.0 (C-4), 126.6, 127.6, 127.9, 128.3, 130.7,
133.9, 141.4 (arom CH, arom. Cipso) ppm.
[24]
R. W. Hoffmann, K. Ditrich, G. Köster, R. Stürmer, Chem.
Ber. 1989, 122, 1783Ϫ1789.
[25]
R. W. Hoffmann, S. Dresely, Chem. Ber. 1989, 122, 903Ϫ909.
[26]
D. S. Matteson, Chem. Rev. 1989, 89, 1535Ϫ1551.
[27]
R. Stürmer, R. W. Hoffmann, Synlett 1990, 759Ϫ761.
[28]
R. Stürmer, Angew. Chem. 1990, 102, 62; Angew. Chem. Int.
Ed. Engl. 1990, 29, 59.
[29]
M. W. Andersen, B. Hildebrand, G. Dahmann, R. W.
Hoffmann, Chem. Ber. 1991, 124, 2127Ϫ2139.
5018
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
Eur. J. Org. Chem. 2004, 5011Ϫ5019

New 1,3-Disubstituted Enantiomerically Pure Allylboronic Esters
FULL PAPER
J. Pietruszka, N. Schöne, Angew. Chem. 2003, 115, 5796Ϫ5799;
Angew. Chem. Int. Ed. 2003, 42, 5638Ϫ5641.
J. Pietruszka, A. Witt, J. Chem. Soc., Perkin Trans. 1 2000,
4293Ϫ4300.
[30]
[49]
[50]
[51]
[52]
[53]
[54]
R. W. Hoffmann, J. J. Wolff, Chem. Ber. 1991, 124, 563Ϫ569.
R. Stürmer, R. W. Hoffmann, Chem. Ber. 1994, 127,
2519Ϫ2526.
H. C. Brown, G. Narla, J. Org. Chem. 1995, 60, 4686Ϫ4687.
P.-Y. Renard, J.-Y. Lallemand, Tetrahedron: Asymmetry 1996,
7, 2523Ϫ2524.
[31]
[32]
J. E. A. Luithle, J. Pietruszka, J. Org. Chem. 1999, 64,
[33]
8287Ϫ8297.
J. E. A. Luithle, J. Pietruszka, Liebigs Ann./Recueil 1997,
2297Ϫ2302.
S. J. Connon, S. Blechert, Angew. Chem. 2003, 115, 1944Ϫ1968;
Angew. Chem. Int. Ed. 2003, 42, 1900Ϫ1923.
A. Fürstner, Angew. Chem. 2000, 112, 3141Ϫ3172; Angew.
Chem. Int. Ed. 2000, 39, 3012Ϫ3043.
K. Nakayama, J. D. Rainier, Tetrahedron 1990, 46, 4165Ϫ4170.
J. Pietruszka, A. Witt, Synlett 2003, 91Ϫ94.
A. Pelter, G. F. Vaughan-Williams, R. M. Rosser, Tetrahedron
1993, 49, 3007Ϫ3034.
Crystallographic data for the structure reported in this paper
have been deposited with the Cambridge Crystallographic Data
Centre as supplementary publication no. CCDC-244944. Cop-
ies of the data can be obtained free of charge on application
to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK [Fax:
(internat.) ϩ 44-1223-336-033; E-mail: deposit@ccdc.cam.ac.uk].
W. R. Roush, K. Ando, D. B. Powers, A. D. Palkowitz, R. L.
Haltermann, J. Am. Chem. Soc. 1990, 112, 6339Ϫ6348.
A. Abiko, J.-F. Liu, S. Masamune, J. Am. Chem. Soc. 1997,
119, 2586Ϫ2587.
[34]
P. Ma, B. Jiang (Du Pont Merck Parmaceutical Co.), Patent
WO 98/01453 (‘‘Method for Preparing α-Chloroboronic Acids
from Mannitol’’) 1998 [Chem. Abstr. 1998, 128, 115078].
D. S. Matteson, Tetrahedron 1998, 54, 10555Ϫ10607.
[35]
[36]
J. Mortier, M. Vaultier, B. Plunian, L. Toupet, Heterocycles
1999, 50, 703Ϫ711.
J. Tailor, D. G. Hall, Org. Lett. 2000, 2, 3715Ϫ3718.
A. Schlapbach, R. W. Hoffmann, Eur. J. Org. Chem. 2001,
323Ϫ328.
A. Zhang, Y. Kan, B. Jiang, Tetrahedron 2001, 57, 2305Ϫ2309.
E. M. Flamme, W. R. Roush, J. Am. Chem. Soc. 2002, 124,
13644Ϫ13645.
[55]
[56]
[57]
[37]
[38]
[39]
[58]
[40]
[41]
M. Deligny, F. Carreaux, L. Toupet, B. Carboni, Adv. Synth.
Catal. 2003, 345, 1215Ϫ1219.
X. Gao, D. G. Hall, J. Am. Chem. Soc. 2003, 125, 9308Ϫ9309.
[42]
[59]
[60]
[61]
[62]
[63]
[64]
[43]
´
B. B. Toure, H. R. Hoveyda, J. Tailor, A. Ulaczyk-Lesanko, D.
G. Hall, Chem. Eur. J. 2003, 9, 466Ϫ474.
[44]
[45]
[46]
´
A. M. Martın Castro, Chem. Rev. 2004, 104, 2939Ϫ3002.
U. Nubbemeyer, Synthesis 2003, 961Ϫ1008.
W. S. Johnson, L. Werthemann, W. R. Bartlett, T. J. Brockson,
T.-T. Li, D. J. Faulkner, M. R. Petersen, J. Am. Chem. Soc.
1970, 92, 741Ϫ743.
H. Meerwein, W. Florian, N. Schön, G. Stopp, Justus Liebigs,
Ann. Chem. 1960, 641, 1Ϫ39.
R. P. Hsung, W. D. Wulff, A. L. Rheingold, J. Am. Chem. Soc.
1994, 116, 6449Ϫ6450.
R. Köster, Y. Morita, Justus Liebigs Ann. Chem. 1967, 704,
70Ϫ90.
[47]
[48]
G. Zweifel, G. M. Clark, N. L. Polston, J. Am. Chem. Soc.
1971, 93, 3395Ϫ3399.
J. A. Miller, G. Zweifel, Synthesis 1981, 288Ϫ289.
Received August 11, 2004
A. E. Wick, D. Felix, K. Steen, A. Eschenmoser, Helv. Chim.
Acta 1964, 47, 2425Ϫ2429.
Eur. J. Org. Chem. 2004, 5011Ϫ5019
www.eurjoc.org
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
5019