Alkynylhalocarbenes 4. Generation of (alk-1-ynyl)halocarbenes from 3-substituted 1,1,1,3-tetrahalopropanes under the action of bases

Russian Chemical Bulletin, International Edition, Vol. 51, No. 7, pp. 1237—1253, July, 2002

1237

Organic Chemistry

Alkynylhalocarbenes

4.* Generation of (alkꢀ1ꢀynyl)halocarbenes from

3ꢀsubstituted 1,1,1,3ꢀtetrahalopropanes under the action of bases**

ꢀ

K. N. Shavrin, V. D. Gvozdev, and O. M. Nefedov

N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences,

47 Leninsky prosp., 119991 Moscow, Russian Federation.

Fax: +7 (095) 135 5328. Eꢀmail: gvozdev@excite.com

When treated with KOH under phaseꢀtransfer catalysis or with Bu^tOK, 3ꢀsubstituted

(alkyl or phenyl) 1,1,3ꢀtribromoꢀ1ꢀfluoropropanes 1a—c exclusively generate previously unꢀ

known (alkꢀ1ꢀynyl)fluorocarbenes 5a—c, which react with olefins to give 1ꢀ(alkꢀ1ꢀynyl)ꢀ1ꢀ

fluorocyclopropanes 6a—h in 12—69% yields. Under analogous conditions, 3ꢀalkylꢀ and

3ꢀarylꢀ3ꢀbromoꢀ1,1,1ꢀtrichloropropanes 2a—c selectively afford (alkꢀ1ꢀynyl)chlorocarbenes

7a—c, which are trapped by olefins to form the corresponding 1ꢀ(alkꢀ1ꢀynyl)ꢀ1ꢀchlorocycloꢀ

propanes 8a—k in 35—70% yields. (Phenylethynyl)chlorocarbene 7a is also selectively generꢀ

ated from 1,1,1,3ꢀtetrachloroꢀ3ꢀphenylpropane (3a) upon its treatment with Bu^tOK. With an

excess of 2,3ꢀdimethylbutꢀ2ꢀene or 2ꢀmethylpropene, carbene 7a yields 1ꢀchloroꢀ1ꢀ(phenylꢀ

ethynyl)cyclopropanes 8a or 8c, respectively. In contrast, 1,1,1,3ꢀtetrachloroheptane 3b and

3ꢀalkylꢀ and 3ꢀphenylꢀ1,1,1,3ꢀtetrabromopropanes 4a,c,f react with bases in the presence of

olefins to give, along with the corresponding 1ꢀ(alkꢀ1ꢀynyl)ꢀ1ꢀhalocyclopropanes 8a,c,d and

11a—f, vinylidenecyclopropanes 12a,c—g, which suggests the generation, under these condiꢀ

tions, both (alkꢀ1ꢀynyl)halocarbenes 7b and 9a—c and vinylidenecarbenes 10 and 11a—c.

The composition and structures of intermediate products in the reactions of tetrahalides 1b,

2a, 2b, 3a, and 3b with Bu^tOK were determined and the mechanisms for carbene generation

in these reactions were proposed.

Key words: 3ꢀsubstituted 1,1,1,3ꢀtetrahalopropanes; dehydrohalogenation, phaseꢀtransꢀ

fer catalysis, (alkꢀ1ꢀynyl)halocarbenes, (alkꢀ1ꢀynyl)halocyclopropanes, cycloaddition.

Earlier,^1,4—6we have proposed a general method for

the generation of (alkꢀ1ꢀynyl)halocarbenes by alkaline

solvolysis of 1,1ꢀdihaloalkꢀ2ꢀynes. This method affords

(alkꢀ1ꢀynyl)chloroꢀ and (alkꢀ1ꢀynyl)bromocarbenes with

alkyl, cycloalkyl, phenyl, and trimethylsilyl substituents

at the triple bond. Our recent studies^2,3revealed that

alkaline solvolysis of accessible 3ꢀsubstituted 1,1,1,3ꢀtetꢀ

rahalopropanes 1—4 also yields (alkꢀ1ꢀynyl)halocarbenes.

This paper presents detailed data on the reactions of variꢀ

* For Part 3, see Ref. 1.

** Preliminary results have been published previously.^2,3

Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1143—1158, July, 2002.

1238

Russ.Chem.Bull., Int.Ed., Vol. 51, No. 7, July, 2002

Shavrin et al.

tetrahalomethanes to accessible terminal olefins.⁷To do

this, the latter were heated with a twoꢀ to fivefold molar

excess of a tetrahalomethane for 4—10 h in the presence

of catalytic amounts of azodiisobutyronitrile (AIBN) or

dibenzoyl peroxide (Scheme 1). 1,1,1,3ꢀTetrachloroꢀ3ꢀ

phenylpropane (3a) was synthesized by addition of CCl₄

to styrene, with a mixture of CuCl₂and Et₂NH₂Cl as a

catalyst.⁸

Scheme 1

The reactions of 3ꢀalkylꢀ and 3ꢀphenylꢀ1,1,3ꢀtriꢀ

bromoꢀ1ꢀfluoropropanes 1a—c with KOH in CH₂Cl₂at

20—40 °C or with Bu^tOK in hexane at 20 °C proceed

through successive elimination of three HBr molecules

to give the corresponding (alkꢀ1ꢀynyl)fluorocarbenes

5a—c, which represent a new class of highly reactive

carbenes. Their trapping by alkenes (2ꢀmethylpropene,

2,3ꢀdimethylbutꢀ2ꢀene, or styrene) affords previously unꢀ

known alkynylfluorocyclopropanes 6a—h in 12—69%

yields (Scheme 2, Table 1). As expected, alkenes that are

unsymmetrical relative to the plane of the πꢀorbitals of

the double bond gave cyclopropanes 6b,e,f,h as mixtures

of cisꢀ and transꢀisomers.

R = Ph (a), Bu (b), Bu^t(c), (Et₂O)₂CH (d), 4ꢀClC₆H₄(e), Me (f).

Reagents and conditions: i) CBr₃F, AIBN; ii) CCl₃Br, AIBN;

iii) CCl₄, (PhCOO)₂; iv) CCl₄, MeCN, CuCl₂, Et₂NH₂Cl;

v) CBr₄, CCl₄, AIBN.

Scheme 3

ous tetrahalides 1—4 with bases in the presence of olefins

as traps for carbenes generated under these conditions.

The starting tetrahalides 1—4, except for 3a, were

prepared by free radical addition of the corresponding

Scheme 2

2a, 7a: R¹= Ph; 2b, 7b: R¹= Buⁿ; 2c, 7c: R¹= Bu^t;

2d, 7d: R¹= (EtO)₂CH; 2e, 7e: R¹= 4ꢀClC₆H₄.

R¹

R²

R³

R⁴

R⁵

8a

8b

8c

8d

8e

8f

8g

8h

8i

Ph

Bu

Bu^t

(EtO)₂CH

4ꢀClC₆H₄

Me

H

Me

Ph

H

Me

H

Me

H

Me

H

Me

H

Me

H

1a, 5a: R¹= Ph; 1b, 5b: R¹= Buⁿ; 1c, 5c: R¹= Bu^t.

R¹

R²

R³

R⁴

R⁵

6a

6b

6c

6d

6e

6f

Ph

Bu

Bu^t

Me

—(CH₂)₄—

Me

H

—(CH₂)₄—

Me

H

Me

H

Me

H

Me

H

Me

H

Me

8j

Me

Ph

Me

H

Me

H

Me

8k

4ꢀClC₆H₄

H

Me

H

6g

Me

6h

Bu^t

—(CH₂)₄—

H

Reagents and conditions: i) Bu^tOK, hexane, 20—60 °C;

ii) KOH, BTEAC (cat.), CH₂Cl₂, 20—40 °C;

iii) Bu^tOK, benzene, 80 °C.

Reagents and conditions: i) Bu^tOK, hexane, 20—60 °C;

ii) KOH, BTEAC (cat.), CH₂Cl₂, 20 °C.

Generation of (alkꢀ1ꢀynyl)halocarbenes

Russ.Chem.Bull., Int.Ed., Vol. 51, No. 7, July, 2002

1239

Table 1. Reactions of 3ꢀsubstituted 1,1,3ꢀtribromoꢀ1ꢀfluoropropanes 1a—c and 3ꢀsubstituted 3ꢀbromoꢀ1,1,1ꢀtrichloropropanes

2a—e with bases in the presence of alkenes R²R⁴C=CR³R⁵

b

Source

of the

carbene

Base,

solvent^a

τ

T

/°C

Carbene

Alkene

Product

(transꢀtoꢀcis

ratio)

Yield

(%)

B.p./°C

(p/Torr)

M.p./°C

/h

R²

R³

R⁴

R⁵

1a

1b

A

B

0.5

2

20

5a

Me

—(CH₂)₄—

Me

H

Me

H

6a

6b

(4.5 : 1)

50^c

69^d

—

140—150 (2)

B

A

B

10

3

8

20

5b

Me

H

—(CH₂)₄—

Me

H

Me

H

6c

6d

6e

48^d

41^d

54^d

130—140 (20)

110—120 (25)

150—170 (12)

(3.7 : 1)

B

12

20

5b

Ph

H

6f

(3.5 : 1)

6g

49^d

110—130 (2)

1c

2a

A

8

65—70

5c

Me

—(CH₂)₄—

Me

H

Me

H

43^d

6^d

130—150 (90)

103—105 (14)

6h

(4.4 : 1)

8a

A

1

20

7а

Me

H

Me

48^c

45^d

59—60

120—123 (2)

8b

(1.4 : 1)

8c

A

B

A

B

1

2

8

3

32

20

65—70

40—45

7а

7b

H

Me

H

Me

Ph

Me

H

Me

H

Me

H

Me

H

43^c

70^e

34^d

52^d

49^d

—

8a

8c

8d

8e

110—111 (2)

150—160 (10)^g

130—140 (1)^g

2b

(3.5 : 1)

8f

A

C

A

48

32

8

1

20

80

20

7b

7c

7d

7e

H

Me

H

35^d

48^e

37^c

35^c

46^c

42^c

130—140 (15)^g

2c

2d

Me

H

Me

H

Me

H

Me

H

8g

8h

8i

8j

—

2e

1

8k

^aA for Bu^tOK in hexane, B for KOH/BTEAC(cat.) in CH₂Cl₂, and C for Bu^tOK in benzene.

^bReaction time.

^cThe product was isolated by column chromatography.

^dThe product was isolated by vacuum distillation.

^eDetermined from the GLC data with the use of an internal standard.

^gThe bath temperature for vacuum microdistillation.

Scheme 4

Analogously, when treated with bases, 3ꢀalkylꢀ and

3ꢀarylꢀ3ꢀbromoꢀ1,1,1ꢀtrichloropropanes 2a—e selectively

generate the corresponding (alkꢀ1ꢀynyl)chlorocarbenes

7a—e, which react with olefins to give alkynylchloroꢀ

cyclopropanes 8a—k in 35—70% yields (Scheme 3, see

Table 1). Cyclopropanes 8b,e were obtained as mixtures

of cisꢀ and transꢀisomers.

(Phenylethynyl)chlorocarbene (7a) was generated by

treating 1,1,1,3ꢀtetrachloroꢀ3ꢀphenylpropane (3a) with

an excess of Bu^tOK in hexane at 20 °C in the presence of

2ꢀmethylpropene and 2,3ꢀdimethylbutꢀ2ꢀene; the corꢀ

responding cyclopropanes 8a,c were selectively obtained

Reagents and conditions: Bu^tOK, hexane, 20 °C.

in 58 and 66% yields, respectively.

The reactions of 1,1,1,3ꢀtetrachloroheptane (3b),

1,1,1,3ꢀtetrabromoꢀ3ꢀphenylpropane (4a), 1,1,1,3ꢀtetraꢀ

bromoꢀ4,4ꢀdimethylpentane (4c), and 1,1,1,3ꢀtetraꢀ

bromobutane (4f) with Bu^tOK in hexane or benzene at

20 °C give, along with (alkꢀ1ꢀynyl)halocarbenes 7b (from

3b) and 9a—c (from 4a, 4c, and 4f), halovinylideneꢀ

carbenes 10 and 11a—c. Their generation becomes eviꢀ

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Shavrin et al.

Scheme 5

R = Ph (4a, 9a, 11a, 12a, 14a), Bu^t(4c, 9b, 11b, 12b, 14b), Me (4f, 9c, 11c, 12c, 14c).

Reagents, conditions, and yields: i) Bu^tOK, hexane, 20 °C; ii) KOH, BTEAC (cat.), CH₂Cl₂, 20—40 °C; the total yield of

compounds 8d and 13 was 48—55%; iii) Bu^tOK, benzene, 20 °C.

dent while analyzing the reaction products, namely,

1ꢀ(alkꢀ1ꢀynyl)ꢀ1ꢀhalocyclopropanes 8d and 12a—e and

halovinylidenecyclopropanes 13 and 14a—d, which were

formed in the presence of alkenes in total 34—55% yields

(Scheme 5, Table 2). Individual 1ꢀbromoꢀ1ꢀ(phenylꢀ

ethynyl)cyclopropanes 12a,d were isolated in 33—51%

yields (12a by recrystallization from methanol and 12d

by distillation in vacuo). Unlike alkyne 12d, isomeric

vinylidenecyclopropane 14d could not be distilled, probꢀ

ably, because of its instability. Note that the reaction

mixture obtained from tetrabromide 4a with Bu^tOK in

hexane in the presence of cyclohexene contained no

bromovinylidenecyclopropane like adduct 13 (GLC and

¹H NMR data), which is probably due to its low stability

and decomposition during the reaction. Only 7ꢀbromoꢀ

7ꢀ(phenylethynyl)norcarane 12e was isolated by vacuum

distillation and characterized as a mixture of transꢀ and

cisꢀisomers.

ynyl)ꢀ1ꢀbromocyclopropanes 12a,d,e (see Table 2), its

reaction with KOH under conditions of phaseꢀtransfer

catalysis in the presence of 2,3ꢀdimethylbutꢀ2ꢀene gave

a 1.6 : 1 mixture of 1ꢀ[(bromo)phenylvinylidene]ꢀ2,2,3,3ꢀ

tetramethylcyclopropane (14a) and 2,2,3,3ꢀtetramethylꢀ

1ꢀ(phenylvinylidene)cyclopropane (15) (NMR and MS

data) in total 45% yield. This indicates that both broꢀ

mo(phenyl)vinylidenecarbene (11a) and phenylvinylꢀ

idenecarbene (16) are generated under these conditions

(Scheme 6).

1,1,1,3ꢀTetrabromoheptane (4b) reacts with Bu^tOK

in benzene at 20 °C in the presence of an excess of

2ꢀmethylpropene to give a mixture of three products in

the 5 : 5 : 1 ratio in total 26% yield, which were identiꢀ

fied as 1ꢀbromoꢀ1ꢀ(hexꢀ1ꢀynyl)ꢀ2,2ꢀdimethylcycloꢀ

propane (12f), 1ꢀ(butyl)bromovinylideneꢀ2,2ꢀdimethylꢀ

cyclopropane (14e), and 1ꢀbromoꢀ1ꢀ(hexꢀ1ꢀenyl)ꢀ2,2ꢀ

dimethylcyclopropane (17) (NMR and MS data). When

diethyl ether or THF were used instead of benzene, a

mixture of the same cyclopropanes was obtained in total

27—31% yield, but the ratio between them was different

(see Table 2). The results obtained suggest that tetraꢀ

bromide 4b generates, under the above conditions,

carbenes 9d, 11d, and 18 (see Scheme 6).

Treatment of tetrachloride 3b with KOH in CH₂Cl₂

in the presence of an excess of 2,3ꢀdimethylbutꢀ2ꢀene at

40—45 °C gave the same products 8d and 13 as with

Bu^tOK. The total yield of these cyclopropanes remained

virtually unchanged, but the content of allene 13 in the

reaction mixture increased from 20 to 50%.

Unlike the reactions of tetrabromide 4a with Bu^tOK,

which mostly yield, in the presence of olefins, 1ꢀ(alkꢀ1ꢀ

The structures of the cyclopropanes synthesized were

proved by elemental analysis, GLꢀMS, and ¹H and

Generation of (alkꢀ1ꢀynyl)halocarbenes

Russ.Chem.Bull., Int.Ed., Vol. 51, No. 7, July, 2002

1241

Table 2. Reactions of 3ꢀsubstituted 1,1,1,3ꢀtetrachloropropanes 3a,b and 3ꢀsubstituted 1,1,1,3ꢀtetrabromopropanes 4a—f with

bases in the presence of alkenes R²R⁴C=CR³R⁵

b

Starting Base,

τ

T

/°C

Carbene

Alkene

R³

Product

(ratio)

Total

yield

(%)

B.p./°C

(p/Torr)

M.p./°C

comꢀ

solꢀ

vent^a

/h

R²

R⁴

R⁵

pound

3a

3b

A

1

48

20

7а

7b, 10

Me

H

Me

H

Me

8a

8c

8d : 13

66^c

58^d

50^d

58—60

110—120 (2)^e

150—160 (10)^e

(4 : 1)

8d : 13

B

C

B

C

D

E

C

80

1

40—45

20

7b, 10

Me

H

Me

H

Me

H

48^d

150—160 (10)^e

—

(1.1 : 1)

12a : 14a

(8 : 1)

12d : 14d

(10 : 1)

4a

9а, 11a

9a

33^f

(pure 12а)

51^d

(pure 12d)

34^d

1

20

118—120 (1)

155—158 (1)

—

1

20

—(CH₂)₄—

H

12e

(5 : 1)^g

4

2

4

20

11a, 16

9d, 11d, 18

9b, 11b

9c, 11c

Me

H

Me

H

14a : 15

(1.6 : 1)

12f : 14e : 17

(5 : 5 : 1)

12f : 14e : 17

(5 : 4 : 1)

12f : 14e : 17

(15 : 1 : 6)

12b : 14b

(1 : 1.4)

12c : 14c

(2.4 : 1)

45^c

26^d

31^d

27^d

24^f

4b

20

120—130 (10)^e

120—130 (12)^e

120—130 (10)^e

—

20

H

20

H

4c

4f

80

Me

20

23^d

100—110 (10)^e

^aA for Bu^tOK in hexane, B for KOH/BTEAC(cat.) in CH₂Cl₂, C for Bu^tOK in benzene, D for Bu^tOK in Et₂O, and E for Bu^tOK

in THF.

^bReaction time.

^cThe product was isolated by column chromatography.

^dThe product was isolated by distillation.

^eThe bath temperature for vacuum microdistillation.

^fThe product was isolated by recrystallization from methanol.

^gThe ratio of transꢀ to cisꢀisomers.

¹³C NMR data (Tables 3—8). The mass spectra of bromoꢀ

and chlorocyclopropanes contain rather intense molecular

ion peaks composed of characteristic isotopic doublets

spaced at 2 amu (their intensity ratios are 1 : 1 and 1 : 3,

respectively). The ¹³C NMR spectra of alkynes 6, 8, and

12 show signals at δ 73—95 characteristic of the triple

bond, while the ¹³C NMR spectra of vinylidenecycloꢀ

propanes 13 and 14 contain signals at δ 95—110 and

180—186 characteristic of the terminal and central carꢀ

bon atoms in the allenic fragment, respectively. The

¹H NMR spectra of the cyclopropanes obtained also

show signals for the protons, which are characteristic of

substituents at the cyclopropane fragment and the mulꢀ

tiple bonds in these compounds.

spectra and considering that J_H,F(trans) < J_H,F(cis) for

cyclopropanes⁹(see Tables 3—5). The other NMR signals

were assigned to the corresponding cisꢀ and transꢀisomers

from their integral intensities. When the transꢀtoꢀcis raꢀ

tio only slightly differed from unity, the content of one

of the isomers in the mixture was increased by colꢀ

umn chromatography or distillation. An analysis of the

¹H NMR spectra of these compounds shows that signals

for the protons in the cisꢀsubstituents relative to the

F atom are shifted downfield compared to signals for

analogous substituents in the transꢀposition. This differꢀ

ence for the cisꢀ and transꢀisomers is due to a strong

deshieldzing effect of the fluorine atom and correlate

with our previous data⁵for (alkꢀ1ꢀynyl)bromoꢀ (12) and

(alkꢀ1ꢀynyl)chlorocyclopropanes (8). It was used to idenꢀ

tify the transꢀ and cisꢀisomers of new halocyclopropanes

8b,e and 12e.

The transꢀ and cisꢀisomers of (alkꢀ1ꢀynyl)fluorocycloꢀ

propanes 6b,e,f,h were distinguished by comparing viciꢀ

1

nal H—F coupling constants in their H and ¹⁹F NMR

1242

Russ.Chem.Bull., Int.Ed., Vol. 51, No. 7, July, 2002

Shavrin et al.

Scheme 6

Reagents, conditions, and yields: i) KOH, BTEAC (cat.), CH₂Cl₂, 20—40 °C; the total yield of 14a+15 was 45%; ii) Bu^tOK,

benzene, 20 °C; iii) Bu^tOK, Et₂O, 20 °C; iv) Bu^tOK, THF, 20 °C; the total yield of 12f+14e+17 was 26—31%.

Table 3. ¹⁹F NMR spectra (CDCl₃, 188 MHz) of

(alkꢀ1ꢀynyl)fluorocyclopropanes 6a—h

To elucidate the pathways through which the discovꢀ

ered carbenes are generated, we tried to determine the

structures of intermediate products in the reactions of

Compound

δ (J/Hz)

Compound

δ (J/Hz)

3ꢀsubstituted 1,1,1,3ꢀtetrahalopropanes 1—4 with bases.

It was shown that treatment of both 3ꢀbromoꢀ1,1,1ꢀ

trichloroꢀ3ꢀphenylpropane (2a) and 1,1,1,3ꢀtetrachloroꢀ

3ꢀphenylpropane (3a) with Bu^tOK (0.5 equiv.) at room

temperature for 30 min affords a mixture containing,

along with the starting tetrahalide, 1,1,3ꢀtrichloroꢀ3ꢀ

6a

–192.0 s

–164.6 t (J = 19) cisꢀ6e

transꢀ6e

–162.4 t (J = 19)

–198.3 s

–175.4 s

–162.8 t (J = 19)

–197.9 s

transꢀ6b

cisꢀ6b

6c

–199.7 s

–191.0 s

6g

transꢀ6h

6d

–181.6 d (J = 18.3) cisꢀ6h

Table 4. Elemental analysis data for (alkꢀ1ꢀynyl)halocyclopropanes 6a—h, 8a—k, and 12a,d,e

Comꢀ

pound

Found

Calculated

Molecular

formula

Comꢀ

pound

Found

Calculated

Molecular

formula

Comꢀ

pound

Found

Calculated

Molecular

formula

(%)

H

(%)

H

(%)

H

C

6a

6b

6c

6d

6e

6f

83.35

8.09

7.92

7.17

C₁₅H₁₇F

C₁₅H₁₅F

C₁₃H₂₁F

C₁₁H₁₇F

C₁₃H₁₉F

C₁₅H₁₇F

C₁₃H₂₁F

C₁₃H₁₉F

8a

8b

8c

8d

8e

8f

77.24

7.46

7.36

6.74

6.91

5.91

6.04

9.82

9.95

7.52

7.36

9.38

9.28

10.17

9.95

C₁₅H₁₇Cl

C₁₄H₁₅Cl

C₁₃H₁₃Cl

C₁₃H₂₁Cl

C₁₅H₁₇Cl

C₁₁H₁₇Cl

C₁₃H₂₁Cl

8h

64.89

9.04

8.96

8.52

8.30

5.91

6.04

5.24

5.06

6.32

6.18

5.22

5.33

5.67

5.49

C₁₄H₂₃O₂Cl

C₁₂H₁₉O₂Cl

C₁₅H₁₆Cl₂

C₁₃H₁₂Cl₂

C₁₅H₁₇Br

83.29

83.89

84.08

79.36

79.54

78.74

78.52

80.60

80.37

83.47

83.29

79.28

79.54

80.19

80.37

77.41

76.91

76.88

67.13

67.43

73.51

73.39

77.23

77.41

71.70

71.53

73.22

73.39

64.98

62.59

62.47

67.13

67.43

65.21

65.29

65.17

64.99

62.61

62.85

65.61

65.47

8i

7.06

10.97

10.78

10.24

10.18

10.06

9.86

7.67

7.92

10.54

10.78

9.75

8j

8k

12a

12d

12e

C₁₃H₁₃Br

6g

6h

8g

C₁₅H₁₅Br

9.86

Generation of (alkꢀ1ꢀynyl)halocarbenes

Russ.Chem.Bull., Int.Ed., Vol. 51, No. 7, July, 2002

1243

1

Table 5. H NMR spectra (CDCl₃, 200.13 MHz, δ, J/Hz) of (alkꢀ1ꢀynyl)halocyclopropanes 6a—h, 8a—k, and 12a—f

Compound

¹H NMR

R²

R¹

R³

1.22 (s, 12 H, 4 Me)

1.20—2.10 (m, 12 H, 4 CH₂and 2 CH)

1.05 (d, 6 H, 2 Me, J = 2.2); 1.08 (d, 6 H, 2 Me, J = 1.5)

R⁴

R⁵

6a

7.30—7.50 (m, 5 H)

trans,cisꢀ6b

7.30—7.60 (m, 5 H)

6c

0.89 (t, 3 H, CH₃, J = 7.3); 1.25—1.60 (m,

4 H, 2 CH₂); 2.28 (dt, 2 H, CH₂C≡,

J = 6.5, J_H,F= 6.5)

6d

0.91 (t, 3 H, CH₃, J = 7.4); 1.25—1.60 (m,

4 Н, 2 CH₂); 2.28 (dt, 2 Н, CH₂C≡,

J = 6.7, J_H,F= 6.7)

0.94 (dd, 1 Н,

СН₂, J = 6.5,

J_H,F= 18.3)

1.21 (d,

3 H, CH₃,

J_H,F= 2.0)

1.15 (d,

3 H, CH₃,

J_H,F= 2.3)

0.73 (dd, 1 Н,

СН₂, J = 6.5,

J_H,F= 7.8)

transꢀ6e

cisꢀ6e

transꢀ6f

cisꢀ6f

0.89 (t, 3 H, CH₃, J = 7.3); 1.05—1.60 (m,

4 H, 2 CH₂); 2.22 (dt, 2 H, CH₂C≡,

J = 6.5, J_H,F= 6.5)

0.91 (t, 3 H, CH₃, J = 7.3); 1.05—1.60 (m,

4 H, 2 CH₂); 2.33 (dt, 2 H, CH₂C≡,

J = 6.7, J_H,F= 6.7)

0.76 (t, 3 H, CH₃, J = 7.3); 1.00—1.80 (m,

4 H, 2 CH₂); 2.07 (dt, 2 H, CH₂C≡,

J = 6.8, J_H,F= 6.8)

1.03—1.95 (m, 10 H, 4 CH₂and 2 CH)*

7.10—7.35

(m, 5 H)

1.00—1.80 (m, 2 H, CH₂)*

2.68 (ddd, 1 H,

CH, J = 8.6, J =

17.7, J = 6.2)

2.41 (ddd, 1 H,

CH, J = 2.5,

0.91 (t, 3 H, CH₃, J = 7.3); 1.00—1.80 (m,

4 H, 2 CH₂); 2.26 (dt, 2 H, CH₂C≡,

J = 6.8, J_H,F= 6.8)

7.10—7.35

(m, 5 H)

J = 8.5, J = 11)

1.07 (d, 6 H, 2 Me, J = 2.2); 1.10 (d, 6 H, 2 Me, J = 1.5)

1.10—1.90 (m, 12 Н, 4 CH₂and 2 CH)

6g

1.24 (s, 9 H, Bu^t)

transꢀ6h

cisꢀ6h

8a

1.27 (s, 9 H, Bu^t)

1.21 (s, 9 H, Bu^t)

1.10—1.90 (m, 12 Н, 4 CH₂and 2 CH)

1.28 (s, 6 H, 2 Me); 1.31 (s, 6 H, 2 Me)

7.28—7.50 (m, 5 H)

transꢀ8b

cisꢀ8b

8c

1.22, 1.25 (both s, 6 H, CMe₂); 1.25—1.45 (m, 4 H, CH, CHMe)

1.22, 1.26 (both s, 6 H, CMe₂); 1.25—1.45 (m, 4 H, CH, CHMe)

7.20—7.40 (m, 5 H, Ph)

1.28 (d, 1 H,

1.42 (s,

1.39 (s,

1.19 (d,

J = 6)

3 H, Me)

1 H, J = 6)

8d

0.91 (t, 3 H, CH₃, J = 7.0); 1.20—1.55 (m,

4 H, 2 CH₂); 2.27 (t, 2 H, CH₂C≡, J = 7.0)

0.81 (t, 3 H, CH₃, J = 7.1); 1.00—2.00 (m,

4 H, 2 CH₂); 2.19 (t, 2 H, CH₂C≡, J = 7.0)

0.97 (t, 3 H, CH₃, J = 7.1); 1.00—2.00 (m,

4 H, 2 CH₂); 2.29 (t, 2 H, CH₂C≡, J = 7.0)

0.88 (t, 3 H, CH₃, J = 7.1); 1.2—1.6 (m,

4 H, 2 CH₂); 2.23 (t, 2 H, CH₂C≡, J = 7.0)

1.15 (s, 9 Н, 3 Me)

1.18 (s, 12 Н, 4 Me)

1.00—2.00 (m, 2 H)*

transꢀ8e

cisꢀ8e

8f

7.20—7.50

(m, 5 Н)

7.20—7.50

(m, 5 Н)

1.05 (d, 1 H,

J = 5.9)

2.80 (dd, 1 Н,

J = 8.0, J = 10)

2.75 (dd, 1 Н,

J = 8.5, J = 9.5)

1.00 (d, 1 H,

J = 5.9)

1.31 (s,

1.23 (s,

3 H, Me)

8g

8h

1.07 (s, 12 Н, 4 Me)

1.17 (s, 6 H, 2 Me); 1.23 (s, 6 H, 2 Me)

1.22 (t, 6 H, 2 CH₂CH₃, J = 7); 3.40—3.72 (m,

4 H, 2 СН₂О); 5.32 (s, 1 H, CH)

8i

1.18 (t, 6 H, 2 CH₂CH₃, J = 7); 3.40—3.70 (m, 1.12 (d, 1 H,

1.27 (s,

1.22 (s,

1.02 (d, 1 H,

4 H, 2 СН₂О); 5.24 (s, 1 H, CH)

7.20—7.40 (m, 4 H, Ph)

7.20—7.40 (m, 4H)

J = 6.5)

3 H, Me)

J = 6.5)

8j

8k

1.25 (s, 6 H, 2 Me); 1.28 (s, 6 H, 2 Me)

1.26 (d, 1 H,

1.40 (s,

1.37 (s,

1.18 (d, 1 H,

J = 5.9)

3 H, Me)

J = 5.9)

12a

12b

12c

12d

7.20—7.50 (m, 5 H, Ph)

1.22 (s, 9 H, 3 Me)

1.92 (s, 3 H, Me)

1.34 (s, 6 Н, 2 Me); 1.35 (s, 6 Н, 2 Me)

1.17 (s, 6 Н, 2 Me); 1.21 (s, 6 Н, 2 Me)

1.19 (s, 6 Н, 2 Me); 1.20 (s, 6 Н, 2 Me)

7.20—7.40 (m, 5 H, Ph)

1.38 (d, 1 H,

1.48 (s,

1.42 (s,

1.27 (d, 1 H,

J = 6)

3 H, Me)

J = 6)

trans,cisꢀ12e 7.20—7.50 (m, 5 H, Ph)

12f 0.92 (t, 3 H, CH₃, J = 7.1); 1.20—1.60 (m,

4 Н, 2 CH₂); 2.24 (t, 2 Н, CH₂C≡, J = 6.9)

1.10—2.20 (m, 10 H, 4 CH₂and 2 CH)

1.14 (d, 1 Н,

СН₂, J = 5.9)

1.26 (s, 3 H, CH₃);

1.35 (s, 3 H, CH₃)

1.09 (d, 1 Н,

СН₂, J = 5.9)

* Overlap with signals for the Bu group.

1244

Russ.Chem.Bull., Int.Ed., Vol. 51, No. 7, July, 2002

Shavrin et al.

Table 6. ¹³C NMR spectra (CDCl₃, 50.32 MHz, δ, J/Hz) and mass spectra of (alkꢀ1ꢀynyl)halocyclopropanes 6a—h, 8a—k,

and 12a—f

Comꢀ

pound

¹³C NMR

MS,

m/z

C≡C

cycloꢀС₃

R¹

R²—R⁵

6a

83.5 (d, ≡CCF,

J = 32.5); 89.8 (d,

PhC≡, J = 10.2)

82.6 (d, ≡CCF,

J = 30); 93.4 (d,

≡CCH₂, J = 10)

87.4 (d, ≡CCF,

J = 30); 85.9 (d,

≡CCH₂, J = 10)

74.2 (d, ≡CCF,

J = 33); 90.8 (d,

≡CCH₂, J = 10)

75.7 (d, CCF,

27.7 (d, 2 CMe₂,

J = 11.5); 80.3 (d,

CF, J = 215)

22.4 (d, 2 CH,

J = 13.5); 76.9 (d,

CF, J = 208)

21.3 (d, 2 CH,

J = 13.5); 73.0 (d,

CF, J = 208)

26.6 (d, 2 CMe₂,

J = 12); 80.6 (d,

CF, J = 214)

23.3 (d, CMe₂, J =

11.7); 26.7 (d, CH₂,

J = 12.2); 76.2 (d,

CF, J = 207.6)

21.3 (d, 2 CH,

J = 14); 77.1 (d,

CF, J = 203)

122.6 (d, C(1),

J = 3); 128.2,

128.4, 131.6

122.3 (d, C(1), Ph,

J = 3); 128.4, 128.7,

131.6 (Ph)

15.5 (d, 2 Me,

J = 8.6);

19.0 (2 Me)

19.0 (2 CH₂);

20.8 (d, 2 CH₂,

J = 3)

17.7 (d, 2 CH₂,

J = 3); 21.4 (d,

2 CH₂, J = 2)

15.6 (d, 2 Me,

J = 10);

19.1 (2 Me)

19.0 (d, (CH₃)₂C,

J = 9.5);

216 [M]⁺

214 [M]⁺

transꢀ6b

cisꢀ6b

6c

128.3, 128.5,

131.7 (Ph)

13.6 (CH₃); 18.7 (d,

CH₂, J = 2.4); 22.0,

30.8 (2 CH₂)

13.6 (CH₃); 18.6,

21.9, 30.6 (3 CH₂)

196 [M]⁺

168 [M]⁺

6d

J = 31.2); 89.3 (d,

C≡CCF, J = 9.4)

22.6 ((CH₃)₂C)

transꢀ6e

cisꢀ6e

73.4 (d, ≡CCF,

J = 30); 94.7 (d,

≡CCH₂, J = 10)

78.7 (d, ≡CCF,

J = 30); 86.6 (d,

≡CCH₂, J = 10)

74.2 (d, ≡CCF,

J = 30); 91.4 (d,

≡CCH₂, J = 10)

13.5 (CH₃); 18.8 (d,

CH₂, J = 2); 21.9,

30.6 (2 CH₂)

13.5 (CH₃); 18.5 (d,

CH₂, J = 2)*

18.9 (2 CH₂);

20.6 (d, 2 CH₂,

J = 2)

17.6 (d, 2 CH₂,

J = 3); 21.4 (d,

2 CH₂, J = 2)

126.6, 128.0,

128.1 (Ph);

194 [M]⁺

20.5 (d, 2 CH,

J = 14)

transꢀ6f

20.2 (d, CH₂, J =

14); 30.0 (d, CH,

J = 11); 73.7 (d,

CF, J = 213)

13.4 (CH₃); 18.4 (d,

CH₂, J = 2.5); 21.6,

30.2 (2 CH₂)

216 [M]⁺

136.2 (C(1), Ph)

cisꢀ6f

77.4 (d, ≡CCF,

J = 32); 87.8 (d,

≡CCH₂, J = 9)

30.8 (d, CH, J =

11); 19.6 (d, CH₂,

J = 13.5); 70.6 (d,

CF, J = 213)

13.6 (CH₃); 18.6 (d,

CH₂, J = 2.5); 22.0,

30.5 (2 CH₂)

126.8, 128.2,

128.5 (Ph);

134.7 (C(1), Ph)

6g

73.4 (d, ≡CCF,

J = 33); 99.1 (d,

≡C—Bu^t, J = 10)

72.0 (d, ≡CCF,

J = 31); 102.7 (d,

≡C—Bu^t, J = 10)

74.1 (d, ≡CCF,

J = 30); 98.3 (d,

≡C—Bu^t, J = 10)

85.2, 88.0

26.5 (d, 2 CMe₂,

J = 12); 80.2 (d,

CF, J = 213)

21.4 (d, 2 CH,

J = 13); 76.9 (d,

CF, J = 204)

20.7 (d, 2 CH,

J = 13); 79.5 (d,

CF, J = 203)

30.2 (2 CMe₂);

49.7 (CCl)

10.0 (CHMe);

28.9 (CMe₂);

45.3 (CCl)

9.5 (CHMe);

27.7 (CMe₂);

45.2 (CCl)

27.8 (d, С(СН₃)₃,

J = 2); 31.0 (3 CH₃)

15.5 (d, 2 Me,

J = 10);

19.0 (2 Me)

18.9 (2 CH₂);

20.7 (d, 2 CH₂,

J = 3)

17.7 (d, 2 CH₂,

J = 3); 21.4 (d,

2 CH₂, J = 2)

18.8 (2 Me);

19.7 (2 Me)

17.3, 24.0,

196 [M]⁺

194 [M]⁺

transꢀ6h

cisꢀ6h

27.9 (d, С(СН₃)₃,

J = 2); 30.9 (3 CH₃)

27.5 (d, С(СН₃)₃,

J = 2); 30.9 (3 CH₃)

8a

123.0 (C(1));

128.2, 128.3

122.8 (C(1))

128.3,

128.4,

122.9 (C(1)) 131.7,

131.8

232, 234 [M]⁺

218, 220 [M]⁺

transꢀ8b

82.8, 86.0

86.6, 89.9

32.1 (3 Me)

cisꢀ8b

16.3, 25.0,

34.4 (3 Me)

8d

80.7, 83.7

77.6, 87.1

29.8 (2 CMe₂);

48.4 (CCl)

25.0 (CH₂);

18.6 (2 Me); 60.7

(2 CH₂); 91.4 (CH)

13.6 (CH₃);

15.1 (2 Me);

19.6 (2 Me)

136.1 (C(1))

212, 214 [M]⁺

128.1,

transꢀ8e

232, 234 [M]⁺

35.2 (CHPh);

33.5 (ССl)

18.5, 21.6,

30.3 (3 CH₂)

128.7,

129.3

(to be continued)

Generation of (alkꢀ1ꢀynyl)halocarbenes

Russ.Chem.Bull., Int.Ed., Vol. 51, No. 7, July, 2002

1245

Table 6 (continued)

Comꢀ

pound

¹³C NMR

MS,

m/z

C≡C

cycloꢀС₃

R¹

R²—R⁵

cisꢀ8e

82.7, 84.4

23.8 (CH₂);

36.4 (CHPh);

34.1 (ССl)

25.4 (CMe₂);

31.8 (CH₂);

41.5 (CCl)

28.8 (2 CMe₂);

49.9 (CCl)

29.8 (2 CMe₂);

48.4 (CCl)

13.9 (CH₃);

18.6 (CH₂);

22.0, 30.6 (2 CH₂)

13.5 (CH₃);

18.5, 21.9,

30.7 (2 CH₂)

27.7 (CMe₃);

31.1 (3 Me)

18.6 (2 Me);

60.7 (2 CH₂);

91.4 (CH)

133.7 (C(1)) 126.7,

128.0,

128.3

22.1, 23.1 (2 Me)

8f

79.6, 84.4

184, 186 [M]⁺

212, 214 [M]⁺

8g

8h

77.1, 94.2

80.7, 83.7

18.8 (2 Me);

19.6 (2 Me)

15.1 (2 Me);

19.6 (2 Me)

258, 260 [M]⁺,

213, 215

[M – EtOH]⁺

230, 232 [M]⁺,

185, 187

8i

78.8, 84.8

84.1, 89.1

82.3, 90.0

25.9 (CMe₂);

31.8 (CH₂);

39.8 (CCl)

30.4 (2 CMe₂);

49.5 (CCl)

14.8 (2 Me); 60.4,

60.5 (2 CH₂);

91.0 (CH)

121.5 (C(1)); 128.6,

133.0 (4 CH);

134.2 (CCl)

121.2 (C(1)); 128.6,

133.0 (4 CH);

134.4 (CCl)

21.7 (2 Me);

22.8 (2 Me)

[M – EtOH]⁺

266, 268 [M]⁺

8j

18.8 (2 Me);

19.7 (2 Me)

8k

26.7 (CMe₂);

32.6 (CH₂);

40.8 (CCl)

22.2, 23.3 (2 Me)

238, 240 [M]⁺

12a

12b

12c

12d

85.6, 89.3

78.5, 94.7

78.8, 82.1

83.6, 90.3

30.1 (2 CMe₂);

43.2 (CBr)

28.8 (2 CMe₂);

44.1 (CBr)

29.0 (2 CMe₂);

44.7 (CBr)

26.1 (CMe₂);

30.2 (CBr);

33.2 (CH₂)

28.0 (2 CH);

34.7 (CBr)

25.3 (2 CH);

29.9 (CBr)

22.7 (CMe₂);

32.7 (CH₂);

31.2 (CBr)

123.1 (C(1)); 128.2,

128.3, 131.8 (Ph)

27.8 (CMe₃);

31.1 (3 Me)

19.5 (2 Me);

21.4 (2 Me)

18.7 (2 CH₂);

21.4 (2 CH₂)

19.4 (2 Me),

21.4 (2 Me)

22.8 (Me);

276, 278 [M]⁺

256, 258 [M]⁺

214, 216 [M]⁺

248, 250 [M]⁺

4.0 (Me)

122.8 (C(1)); 128.3,

128.4, 131.8

24.9 (Me)

transꢀ12e

cisꢀ12e

12f

87.4, 89.3

80.5, 93.4

81.1, 84.9

122.8 (C(1)) 128.2,

128.3,

122.9 (C(1)) 128.4,

128.5

13.6 (CH₃); 18.7,

22.0, 30.8 (3 CH₂)

20.1 (2 CH₂);

20.7 (2 CH₂)

20.6 (2 CH₂);

24.6 (2 CH₂)

22.8 (Me);

274, 276 [M]⁺

228, 230 [M]⁺

24.9 (Me)

* The other signals overlap signals for transꢀ6e.

1

Table 7. H NMR spectra (CDCl₃, 200.13 MHz, δ, J/Hz) of (organyl)halovinylidenecyclopropanes 13 and 14a—e

Comꢀ

pound

¹H NMR

R², R⁵

R¹

R³, R⁴

13

0.89 (t, 3 H, CH₃in Bu, J = 7); 1.20—1.55 (m,

4 H, 2 CH₂); 2.36 (t, 2 H, —CH₂CCl=, J = 7)

7.15—7.60 (m, 5 H, Ph)

1.16 (s, 9 H, 3 Me)

2.31 (s, 3 H, Me)

7.15—7.60 (m, 5 H, Ph)

0.91 (t, 3 H, CH₃in Bu, J = 7); 1.20—1.55 (m, 1.52 (d, 1 H, CH₂, J = 7.3);

4 H, 2 CH₂); 2.47 (t, 2 H, —CH₂CBr=, J = 7) 1.49 (d, 1 H, CH₂, J = 7.3)

1.26 (s, 6 H, 2 Me); 1.29 (s, 6 H, 2 Me)

14a

14b

14c

14d

14e

1.43 (s, 6 H, 2 Me); 1.47 (s, 6 H, 2 Me)

1.25 (s, 6 Н, 2 Me); 1.28 (s, 6 Н, 2 Me)

1.27 (s, 12 Н, 4 Me)

1.78 (s, 2 H, СН₂)

1.42 (3 H, Me); 1.45 (s, 3 H, Me)

1.29 (s, 3 H, Me); 1.27 (s, 3 H, Me)

1246

Russ.Chem.Bull., Int.Ed., Vol. 51, No. 7, July, 2002

Shavrin et al.

Table 8. ¹³C NMR spectra (CDCl₃, 50.32 MHz, δ) and mass spectra (m/z) of (organyl)halovinylidenecyclopropanes 13 and 14a—e

Comꢀ

pound

¹³C NMR

MS

C=С=С

=С=

180.8

cycloꢀС₃

R¹

R²—R⁵

13

107.3, 107.6

13.9 (СH₃CH₂—); 21.0, 21.1, 21.8, 29.3, 29.5,

36.9 (2 CMe₂, 2 С(CH₃), CH₂—CH₂—CH₂in Bu)

212, 214 [M]⁺

214, 216 [M]⁺

14a

94.7, 106.1

186.0

32.1 (2 C(Me)₂)

125.9, 128.2, 128.8 (Ph);

135.9 (C(1))

21.1 (2 Me); 21.6 (2 Me)

14b

14c

14d

14e

105.7, 108.1

90.1, 105.8

180.3

182.0

29.0 (CMe₂)

29.3 (CMe₂)

29.1 (3 Me); 37.6 (CMe₃) 20.9 (2 Me); 21.0 (2 Me)

26.4 (Me) 20.9 (2 Me); 21.3 (2 Me)

256, 258 [M]⁺

214, 216 [M]⁺

248, 250 [M]⁺

228, 230 [M]⁺

—

96.2, 98.0

183.4

13.9 (СH₃CH₂—); 21.7, 22.5, 23.9, 24.7, 30.3, 31.2 (CMe₂, 2 С(CH₃),

CH₃—CH₂—CH₂— in Bu, CH₂in cycloꢀC₃H₂); 38.5 (СН₂СBr=)

phenylpropꢀ1ꢀene (19a) (Scheme 7). The latter was obꢀ

tained in the individual state in 28% yield by refluxing

tetrahalide 2a with triethylamine for 8 h. Note that the

formation of trichloride 19a from 2a (and possibly

from 3a) is most probably due to the allylic rearrangeꢀ

ment¹⁰of 1,1,1ꢀtrichloroꢀ3ꢀphenylpropꢀ2ꢀene (20a) iniꢀ

tially formed through elimination of HBr.

¹H NMR spectroscopy. The spectrum of the reaction

mixture shows a singlet at δ 6.57 corresponding to the

allene proton and a multiplet for the phenyl protons at

δ 7.30—7.50. Its ¹³C NMR spectrum exhibits a sigꢀ

nal at δ 200.9 for the spꢀhybridized carbon atom in

the allene fragment, a signal at δ 127 for the CCl₂

group, and a signal at δ 106 for the =CH group,

which, without proton decoupling, appears as a doublet

with a coupling constant of 165 Hz. Allene 22a is

rather labile and decomposes almost completely even in

deuterochloroform at ∼20 °C over a few days (GLC and

¹H NMR data).

Scheme 7

The resulting mixture of compounds 21a and 22a

react with Bu^tOK and an excess of 2,3ꢀdimethylbutꢀ

2ꢀene to give 1ꢀchloroꢀ2,2,3,3ꢀtetramethylꢀ1ꢀ(phenylꢀ

ethynyl)cyclopropane (8a) in 55% yield; the reaction

mixture contained no starting dichlorides. When the iniꢀ

tial ratio between dichlorides 21a and 22a was changed

from 3 : 1 to 1 : 1, the yield of cycloadduct 8a remained

unchanged, being the same as for dichloride 21a used

alone (55%).

Reagents and conditions: Bu^tOK (0.5 equiv.), hexane, 20 °C.

The treatment of trichloride 19a with an excess of

Bu^tOK in the presence of excess 2,3ꢀdimethylbutꢀ2ꢀene

gave the corresponding cyclopropane 8a in 46% yield.

During the course of the reaction, 3,3ꢀdichloroꢀ1ꢀphenylꢀ

propꢀ2ꢀyne (21a) and 1,1ꢀdichloroꢀ3ꢀphenylpropaꢀ

1,2ꢀdiene (22a) were detected in the reaction mixꢀ

ture. These compounds proved to be identical with

authentic samples obtained in an independent way

(GLC data).

We found⁵that treatment of 3,3ꢀdichloroꢀ1ꢀphenylꢀ

propꢀ2ꢀyne (21a) with a deficient amount of Bu^tOK in

hexane at ∼20 °C yields a mixture of dichloride 21a and

allene 22a in the ratios from 5 : 1 to 1 : 1, depending on

the amount of the base and the reaction time. However,

the conversion of the starting alkyne 21a into allene

22a was incomplete since the reaction mixture, for

Bu^tOK > 0.5 equiv., undergoes significant resinification,

and no increase in the content of 22a resulted. The presꢀ

ence of allene 22a in the reaction mixture was proved by

Hence, it can be concluded that cyclopropane 8a is

formed both from dichloroalkyne 21a and from dichloroꢀ

allene 22a. Apparently, when treated with Bu^tOK, both

lose the proton to give anion 23, which is transformed,

through the elimination of the chloride anion, into

chloro(phenylethynyl)carbene 7a; the latter is trapped

by 2,3ꢀdimethylbutꢀ2ꢀene (Scheme 8).

Moreover, using the Moss method,¹¹we demonstrated

that the carbenes generated from both dichloride 21a

and trichloro bromide 2a are of the same nature. For this

purpose, we used the method of competitive reactions to

determine the relative reactivities (k_i/k₀) of carbene 7a

generated under the action of Bu^tOK from the above

halides with respect to a set of methylolefins with

2ꢀmethylpropene as a reference (k_i/k₀= 1). The results

obtained are given in Table 9. While comparing the relaꢀ

tive reactivities of chloro(phenylethynyl)carbene generꢀ

ated from dichloride 21 and that from tetrahalide 2a,

one can see that they are equal to within the measureꢀ

Generation of (alkꢀ1ꢀynyl)halocarbenes

Russ.Chem.Bull., Int.Ed., Vol. 51, No. 7, July, 2002

1247

Scheme 8

Scheme 9

Reagents and conditions: Bu^tOK, hexane, 20 °C.

Thus, the results obtained indicate that the reactions

of halides 2a and 3a with Bu^tOK in the presence of

alkenes follow Scheme 10, proceeding through an equiꢀ

librium mixture of dichloroallene 22a and dichloroꢀ

alkyne 21a.

Reagents and conditions: Bu^tOK, hexane, 20 °C, 30—90 min.

When 1,1,3ꢀtribromoꢀ1ꢀfluoroheptane (1b) was

treated with an equimolar amount of Bu^tOK in the abꢀ

sence of olefins, the reaction mixture contained, along

with the starting halide, transꢀ1,1ꢀdibromoꢀ1ꢀfluoroheptꢀ

2ꢀene (24) and the Eꢀ and Zꢀisomers of 1,3ꢀdibromoꢀ1ꢀ

fluoroheptꢀ1ꢀene (25) in the ratio 1 : 1.8 : 0.9 : 0.75,

respectively. Addition of Bu^tOK to the resulting mixꢀ

ture gave 1ꢀbromoꢀ1ꢀfluoroheptaꢀ1,2ꢀdiene (26) and

1ꢀbromoꢀ1ꢀfluoroheptꢀ2ꢀyne (27).

Table 9. Relative reactivity of chloro(phenylꢀ

ethynyl)carbene 7a generated from dichloride 21a (A)

and from trichloro bromide 2a (B)

Alkene

A

B

2ꢀMethylpropene

2ꢀMethylbutꢀ2ꢀene

2,3ꢀDimethylbutꢀ2ꢀene

cisꢀButꢀ2ꢀene

1.0

2.1 0.13

4.9 0.21

0.34 0.02

1.9 0.15

5.0 0.17

0.36 0.03

The structures of all intermediate halides were proved

1

by H and ¹⁹F NMR spectroscopy and GLꢀMS analysis.

ment error, which confirms the identity of the resulting

intermediates.

The configuration of the double bond in compounds 24

and 25 was determined from the values of vicinal H—H

(for 24) and H—F (for 25) coupling constants.

It should be noted that a set of signals correspondꢀ

ing to the CH=CH fragment in compound 24 has a

very complex structure since the both protons have

close chemical shifts and there are a lot of H—H and

H—F spinꢀspin couplings. To calculate precise chemiꢀ

cal shifts and coupling constants, we calculated the

Direct evidence that 1,1ꢀdihaloꢀ3ꢀorganylꢀ1,2ꢀdienes

22 are precursors of (alkꢀ1ꢀynyl)halocarbenes was proꢀ

vided⁵by the generation of chloro(3,3ꢀdiethoxypropꢀ1ꢀ

ynyl)carbene (7d) in the reaction of 1,1ꢀdichloroꢀ4,4ꢀ

diethoxybutaꢀ1,2ꢀdiene (22b) with Bu^tOK. Its trapping

by 2,3ꢀdimethylbutꢀ2ꢀene afforded the corresponding

cyclopropane 8h in 48% yield (Scheme 9).

Scheme 10

Reagents and conditions: i) Bu^tOK, hexane, 20 °C.

1248

Russ.Chem.Bull., Int.Ed., Vol. 51, No. 7, July, 2002

Shavrin et al.

Scheme 11

Reagents and conditions: i) Bu^tOK, hexane, 20—60 °C.

1

spectrum* and corrected the initial parameters to miniꢀ

mize a discrepancy between the calculated and experiꢀ

mental data. Based on the coupling constant between

the olefinic protons (15.5 Hz), obtained by this iterative

procedure, we unambiguously assigned the transꢀstrucꢀ

ture to alkene 24.

and CHBr groups at δ 4.6—4.8. The H NMR spectrum

of trichloroalkene 20b with the internal double bond

shows a set of signals (d and dt) characteristic of

the olefinic protons in the CH=CH—CH₂fragment.

The vicinal coupling constant (15.5 Hz) indicates the

transꢀconfiguration of the double bond in 20b.

For the major isomer of compound 25 in the reaction

mixture, J_H,F= 28 Hz, while for the minor isomer this

value was 10 Hz. Insofar as J_cis< J_transfor fluoroalkenes,⁹

Eꢀhalide 25 proves to be dominant.

Scheme 12

1

The H NMR spectrum of allene 26 contains a charꢀ

acteristic signal for the allene proton at δ 5.97 (td, J_H,F

=

1.6 Hz); this coupling constant is consistent with the

¹⁹F NMR data for this compound. As expected, the

¹H NMR spectrum of alkyne 27 shows a doublet of

triplets for the CHBrF group at δ 7 (J_H,F= 52 Hz,

J_H,H= 1.7 Hz) because of the spinꢀspin coupling of the

proton with the F atom and with the CH₂group through

the triple bond.

The data obtained suggest that carbene 5b is generꢀ

ated from tetrahalides 1b according to Scheme 11. Apꢀ

parently, the generation of other (alkꢀ1ꢀynyl)fluoroꢀ

carbenes 5 occurs analogously.

Reagents and conditions: Bu^tOK, hexane, 20 °C.

Further reactions of the mixtures obtained with Bu^tOK

resulted in carbene generation, and intermediate prodꢀ

ucts of their monodehydrohalogenation were not isoꢀ

lated or characterized. Insofar as tetrahalide 2b selecꢀ

tively generates only chloro(hexꢀ1ꢀynyl)carbene 7b (see

Scheme 3, Table 1), both chlorides 19c and 20b seem to

be its precursors. Thus, carbene 7b is probably generꢀ

ated by analogy with (alkynꢀ1ꢀyl)fluorocarbene (see

Scheme 11) through the formation of an equilibrium

mixture of 1,1ꢀdichloroheptꢀ2ꢀyne (21b) and 1,1ꢀdiꢀ

chloroheptaꢀ1,2ꢀdiene (22c) (Scheme 13).

The generation of butyl(chloro)vinylidenecarbene (10)

in the reaction of tetrachloride 3b with Bu^tOK (see

Scheme 5) most probably proceeds via dehydrochlorinaꢀ

tion of trichloride 19b into 1,3ꢀdichloroheptꢀ1ꢀyne (28),

which undergoes γꢀelimination of HCl, by analogy

Unlike halides 2a and 3a, compounds 2b and 3b reꢀ

act with a deficient amount of Bu^tOK (Scheme 12) to

give a mixture of isomeric alkenes containing the termiꢀ

nal (19b,c) and internal double bond (20b) in the ratios

1 : 1.2 and 1 : 3.5, respectively. Their structures were

1

determined from the H NMR spectra of the reaction

mixture. Trihalides 19b,c give doublets for olefinic proꢀ

tons at δ 5.95—6.10 and doublets of triplets for the CHCl

* To determine the chemical shifts and the coupling constants

for a multiplet corresponding to this fragment, the spectral

parameters were calculated and corrected to minimize a disꢀ

crepancy between the calculated and experimental data (the

NUTS program, version 4.35). The resulting chemical shifts

and coupling constants are δ(C(H)₂CH_b=) 5.95 (J_a,b= 6.9 Hz,

J_b,c= 15.5 Hz, J_H,F= –1 Hz); δ(CBr₂FCH_c=) 6.04 (J_a,c

–1.5 Hz, J_b,c= 15.5 Hz, J_H,F= 16.4 Hz).

=

Generation of (alkꢀ1ꢀynyl)halocarbenes

Russ.Chem.Bull., Int.Ed., Vol. 51, No. 7, July, 2002

1249

Scheme 13

Reagents and conditions: i) Bu^tOK, hexane, 20—60 °C.

with other vinylidenecarbenes,¹²to give carbene 10

Scheme 15

(Scheme 14).

Scheme 14

Reagents and conditions: i) Bu^tOK, hexane, 20—60 °C.

Reagents and conditions: i) KOH, CH₂Cl₂, BTEAC, 20 °C.

Apparently, the reactions of tetrabromides 4a,c,f with

Bu^tOK proceed analogously, generating (alkꢀ1ꢀynyl)broꢀ

mocarbenes 9a—c and bromovinylidenecarbenes 11a—c

(see Scheme 5). These carbenes are trapped by alkenes

to give isomeric bromineꢀcontaining cyclopropanes 12

and 14. Phenylvinylidenecarbene (16) is most likely genꢀ

erated from tetrabromide 4a under conditions of phaseꢀ

transfer catalysis (see Scheme 6) via elimination of two

HBr molecules followed by KOHꢀinitiated debromination

of intermediate 1,1ꢀdibromoꢀ3ꢀphenylpropaꢀ1,2ꢀdiene

(29) (Scheme 15). The possibility of such processes has

been reported earlier.¹³

(phaseꢀtransfer catalysis) or Bu^tOK exclusively give

(alkꢀ1ꢀynyl)fluorocarbenes, which belong to a new class

of carbene intermediates. Under analogous condiꢀ

tions, 3ꢀarylꢀ and 3ꢀalkylꢀ3ꢀbromoꢀ1,1,1ꢀtrichloroꢀ

propanes generate (alkꢀ1ꢀynyl)chlorocarbenes. However,

the behavior of 3ꢀsubstituted 1,1,1,3ꢀtetrachloroꢀ or

1,1,1,3ꢀtetrabromopropanes in the presence of bases is

Scheme 16

The formation of small amounts of a third product,

namely, cyclopropane 17, from tetrabromide 4b suggests

the generation of (transꢀhexꢀ1ꢀenyl)bromocarbene (18)

(see Scheme 6), which can be due to partial debrominaꢀ

tion of intermediate transꢀ1,1,1ꢀtribromoheptꢀ2ꢀene (30)

under the action of Bu^tOK.

Hence, we found that the reactions of 3ꢀalkylꢀ and

3ꢀphenylꢀ1,1,3ꢀtribromoꢀ1ꢀfluoropropanes with KOH

Reagents and conditions: i) Bu^tOK, hexane, 20—60 °C.

1250

Russ.Chem.Bull., Int.Ed., Vol. 51, No. 7, July, 2002

Shavrin et al.

(3 Me); 36.3 (CMe₃); 57.6 (d, CH₂CBr₂F, J = 18 Hz);

61.0 (CHBr); 94.3 (d, CBr₂F, J = 324 Hz).

largely determined by the nature of both the 3ꢀsubstituꢀ

ent and the halogen atoms and also depend on the reꢀ

action conditions. When they are used as carbene

sources, halovinylidenecarbenes are generated along with

(alkynꢀ1ꢀyl)halocarbenes; in some cases, vinylideneꢀ and

bromo(vinyl)carbenes are also formed. The mechanisms

for these complex multistep reactions were proposed.

Synthesis of 1ꢀ(alkꢀ1ꢀynyl)ꢀ1ꢀfluorocyclopropanes (6a—h)

and 1ꢀ(alkꢀ1ꢀynyl)ꢀ1ꢀchlorocyclopropanes (8a—k) from 3ꢀsubꢀ

stituted 1,1,3ꢀtribromoꢀ1ꢀfluoropropanes (1a—c) and 3ꢀsubstiꢀ

tuted 3ꢀbromoꢀ1,1,1ꢀtrichloropropanes (2a—e) (general proceꢀ

dure). A. Using Bu^tOK as a base. A solution of a starting

tetrahalide (2 mmol) in 1 mL of a solvent specified in Table 1

was added at ∼20 °C to a mixture of Bu^tOK (1350 mg, 12 mmol)

and a starting alkene (6 mmol) in 6 mL of the same solvent.

The reaction mixture was stirred (the reaction duration and

temperature are given in Table 1) until the reaction was comꢀ

pleted (monitoring by GLC). Then the reaction mixture was

treated with water, and the organic layer was separated. The

organic material was extracted from the aqueous phase with

ether (3×10 mL). The combined organic layers were dried with

magnesium sulfate, and the solvent was removed. Cycloproꢀ

pane 6 or 8 was isolated from the residue by vacuum distillation

or by column chromatography in hexane (see Table 1). The

yields, boiling points, and the ratios between the cisꢀ and

transꢀisomers of compounds 6 and 8 are given in Table 1. Their

spectral characteristics are presented in Tables 3—5.

B. Using KOH as a base. A solution of a starting tetrahalide

(2 mmol) in 1 mL of CH₂Cl₂was added to a mixture of KOH

(1.8 g, 30 mmol), one drop of water, BTEAC (50 mg), and a

starting alkene (6 mmol) in CH₂Cl₂(10 mL). The solvent was

preliminarily refluxed over KOH with BTEAC and then disꢀ

tilled to remove an impurity of chloroform. The reaction mixꢀ

ture was stirred (the reaction duration and temperature are

given in Table 1) until the reaction was completed (monitoring

by GLC). The product was isolated as described above for

Bu^tOK as a base (see Table 1). The yields, boiling points, and

the ratios between the cisꢀ and transꢀisomers of cyclopropanes

6 and 8 are given in Table 1. Their spectral characteristics are

presented in Tables 3—6.

Reaction of 1,1ꢀdichloroꢀ3ꢀphenylpropꢀ2ꢀyne (21a) with a

deficient amount of Bu^tOK. Generation of chloro(phenylꢀ

ethynyl)carbene (7a) from a mixture of dichloride 21a and

1,1ꢀdichloroꢀ3ꢀphenylpropadiene (22a). Freshly prepared Bu^tOK

(50 mg, 0.44 mmol) was added at ∼20 °C to a solution of

dichloride 21a (185 mg, 1 mmol) in 3 mL of hexane. After

10 min, the content of the starting dichloride was reduced to

82%, and allene 22a (18%) was detected in the reaction mixꢀ

ture (GLC data). The ratio of compound 21a to 22a became

1 : 1 after 30 min. When the reaction was carried out for a

longer period of time or with a larger amount of Bu^tOK (in

separate experiments), the relative content of allene 22a in the

mixture did not increase because of intense resinification. The

mixture of the starting dichloride and allene 22a was isolated

by passing the reaction mixture through a thin layer of silica

gel. The solution obtained was then used in reactions with

Bu^tOK in the presence of 2,3ꢀdimethylbutꢀ2ꢀene. Product 22a

was characterized by the NMR spectra of the reaction mixture.

¹H NMR, δ: 6.57 (s, 1 H, PhCH); 7.20—7.50 (m, 5 H, 2 Ph).

¹³C NMR, δ: 106.1 (PhCH); 127.0 (CCl₂); 127.4, 129.8,

132.0 (Ph); 139.4 (C(1), Ph); 201.0 (=C=).

Experimental

GLC analysis of the starting reagents and the products was

carried out on a HewlettꢀPackard 5890 Series II instrument

with a capillary column 30 m×0.153 mm and a HewlettꢀPackard

3396A automated integrator. When the yields of the known

compounds were determined by GLC, the products were idenꢀ

tified by comparing their retention times with those of authenꢀ

1

tic samples. H and ¹³C NMR spectra were recorded on Bruker

ACꢀ200p and Bruker AMꢀ300 spectrometers in CDCl₃with

tetramethylsilane as the internal standard. IR spectra were reꢀ

corded on a Perkin—Elmer 580 spectrophotometer in CCl₄.

Mass spectra were recorded on a Finningan MAT INCOSꢀ50

GLꢀMS spectrometer.

The starting 3ꢀsubstituted 1,1,1,3ꢀtetrahalopropanes

2a—e, 3b, and 4a—c,f were prepared as described in Ref. 7;

1,1,1,3ꢀtetrachloroꢀ3ꢀphenylpropane (3a) was obtained accordꢀ

ing to the known procedure.⁸

1,1ꢀDichloroꢀ3ꢀphenylpropꢀ2ꢀyne (19a) and 1,1ꢀdichloroꢀ

4,4ꢀdiethoxybutaꢀ1,2ꢀdiene (22b) were prepared as described

earlier.⁵Tetrabromomethane,¹⁴tribromofluoromethane,¹⁵and

bromotrichloromethane¹⁶were synthesized according to the

known procedures.

Synthesis of 3ꢀsubstituted 1,1,3ꢀtribromoꢀ1ꢀfluoropropanes

(1a—c). Azodiisobutyronitrile (50 mg, 0.3 mmol) was added

to a mixture of a starting alkene (styrene, hexꢀ1ꢀene, or

3,3ꢀdimethylbutꢀ1ꢀene) (10 mmol) and tribromofluoromethane

(13.5 g, 50 mmol). The reaction mixture was heated at 75 °C

for 4—12 h, and the excess of tribromofluoromethane was reꢀ

moved at atmospheric pressure (b.p. 106—108 °C) and then at

10—15 Torr. The product was isolated from the residue by

vacuum distillation.

1,1,3ꢀTribromoꢀ1ꢀfluoroꢀ3ꢀphenylpropane (1a), b.p.

112—114 °C (1 Torr). The yield was 30% (from styrene).

¹H NMR, δ: 3.71—3.84 (m, 2 H, CH₂); 5.37 (dd, 1 H, CHBr,

J = 6.2 Hz, J = 7.4 Hz); 7.30—7.50 (m, 5 H, Ph). ¹³C NMR, δ:

47.7 (CHBr); 60.8 (d, CH₂CBr₂F, J = 18 Hz); 92.3 (d, CBr₂F,

J = 324 Hz); 127.7, 128.9, 129.0 (Ph); 140.2 (C(1), Ph).

1,1,3ꢀTribromoꢀ1ꢀfluoroheptane (1b), b.p. 83—84 °C

1

(2 Torr). The yield was 78% (from hexꢀ1ꢀene). H NMR, δ:

0.93 (t, 3 H, CH₃, J = 7 Hz); 1.25—1.65 (m, 4 H, 2 CH₂);

1.70—2.05 (m, 2 H, CH₂CHBr); 3.26 (ddd, 1 H, CH₂CFBr₂,

J = 17 Hz, J = 7.5 Hz, J_H,F= 17 Hz); 3.43 (ddd, 1 H,

CH₂CFBr₂, J = 17 Hz, J = 6.2 Hz, J_H,F= 23 Hz); 4.30 (ddt,

1 H, CHBr, J = 6.2 Hz, J = 7.5 Hz, J = 7 Hz). ¹³C NMR, δ:

14.0 (Me); 21.9, 29.2, 38.2 (3 CH₂); 49.6 (CHBr); 60.4 (d,

CH₂CBr₂F, J = 18 Hz); 93.3 (d, CBr₂F, J = 323 Hz).

2,3ꢀDimethylbutꢀ2ꢀene (252 mg, 3 mmol) and tridecane

(100 mg) were added to a solution of the aforesaid 1 : 1 mixture

of dichlorides 21a and 22a. The resulting mixture was analyzed

by GLC with a preꢀcalibrated detector. The amount of dichloꢀ

rides 21a and 22a in the mixture was determined from the ratio

1,1,3ꢀTribromoꢀ1ꢀfluoroꢀ4,4ꢀdimethylpentane (1c), b.p.

80—82 °C (3 Torr). The yield was 58% (from 3,3ꢀdimethylbutꢀ

1

1ꢀene). H NMR, δ: 1.11 (s, 9 H, 3 Me); 3.26—3.41 (m, 2 H,

CH₂CBr₂F); 4.00—4.07 (m, 1 H, CHBr). ¹³C NMR, δ: 27.2

Generation of (alkꢀ1ꢀynyl)halocarbenes

Russ.Chem.Bull., Int.Ed., Vol. 51, No. 7, July, 2002

1251

of their peak areas to that of tridecane. Potassium tertꢀbutoxide

(224 mg, 2 mmol) was added, and the reaction mixture was

kept for 30 min and treated with 5 mL of water. The organic

layer was separated, and the organic material was extracted

from the aqueous phase with hexane (2×5 mL). The combined

organic layers were analyzed by GLC with a preꢀcalibrated

detector. The yield of 1ꢀchloroꢀ2,2,3,3ꢀtetramethylꢀ1ꢀ(phenylꢀ

ethynyl)cyclopropane (8a) (55% from both dichlorides 21a and

22a) was determined from the ratio of its peak area to that of

tridecane. In an analogous reaction involving a 3 : 1 mixture

of dichlorides 21a and 22a, the yield of cyclopropane 8a

was 56%.

B. When chloro(phenylethynyl)carbene (7a) was generated

from tetrahalide 2a (200 mg, 0.66 mmol), the corresponding

stoichiometric amount of Bu^tOK (220 mg, 2 mmol) was taken.

The k_i/k₀values obtained are given in Table 9.

Synthesis of cyclopropanes 8a and 8c by the reactions of

1,1,1,3ꢀtetrachloroꢀ3ꢀphenylpropane (3a) with Bu^tOK in the

presence of alkenes. The reaction was carried out according to

the general procedure for the preparation of 1ꢀ(alkꢀ1ꢀynyl)ꢀ1ꢀ

chlorocyclopropanes (see above) with the use of Bu^tOK as a

base. After the reaction was completed (over 1 h in hexane at

∼20 °C), the reaction product was isolated by column chromaꢀ

tography in hexane (cyclopropane 8a) or by vacuum microꢀ

distillation (cyclopropane 8c). The yields of compounds 8a and

When dichloride 21a was used alone (instead of a mixture

of chlorides 21a and 22a), the yield of cyclopropane 8a was

60% (GLC data).

1

8c were 66 and 58%, respectively. Their H NMR spectra are

identical with those of the same cyclopropanes obtained from

tetrahalide 2a.

While carrying out an analogous reaction without addition

of tridecane, cyclopropane 8a (98 mg, 42%) was isolated from

the reaction mixture by column chromatography in hexane.

The purity of the product was >95% (GLC and ¹H NMR data).

Synthesis of 1ꢀchloroꢀ1ꢀ(3,3ꢀdiethoxypropꢀ1ꢀynyl)ꢀ2,2,3,3ꢀ

tetramethylcyclopropane (8h). A solution of 1,1ꢀdichloroꢀ4,4ꢀ

diethoxybutaꢀ1,2ꢀdiene (22b) (560 mg, 2.65 mmol) in 1 mL of

hexane was added at ∼20 °C to a mixture of 2,3ꢀdimethylbutꢀ

2ꢀene (670 mg, 8 mmol) and Bu^tOK (582 mg, 5.2 mmol) in

5 mL of hexane. The reaction mixture was stirred for 2 h and

treated with water. The organic layer was separated, and the

organic material from the aqueous phase was extracted with

hexane (3×10 mL). The combined organic layers were dried

with magnesium sulfate, and the solvent was evaporated. Colꢀ

umn chromatography of the residue in hexane gave cycloproꢀ

pane 8h (327 mg, 48%). The spectral data of the product obꢀ

tained are given in Tables 4 and 5.

Determination of the relative reactivity of chloro(phenylꢀ

ethynyl)carbene (7a) generated from 3,3ꢀdichloroꢀ1ꢀphenylꢀ

propyne (21a) and 3ꢀbromoꢀ1,1,1ꢀtrichloroꢀ3ꢀphenylpropane (2a)

under the action of Bu^tOK. A. Potassium tertꢀbutoxide (110 mg,

1 mmol) was added to a solution of 2,3ꢀdimethylbutꢀ2ꢀene and

2ꢀmethylbutꢀ2ꢀene (10—15 mmol) in 25 mL of benzene. The

reaction mixture was cooled to –10 to –20 °C, and 2ꢀmethylꢀ

propene (350—650 mg, 7—12 mmol) was added using an evapoꢀ

ration—condensation method. The flask was hermetically sealed

with a rubber plug and warmed to ∼20 °C. A solution of the

starting dichloride 21a (1 mmol) in 1—2 mL of hexane was

added. After 30 min, the reaction mixture was stratified by

adding water, and the organic layer was analyzed five times by

GLC. An outlier (if present) was rejected, while the other

results were averaged. The mass fractions of cyclopropanes 8

were determined with a detector preꢀcalibrated against authenꢀ

tic samples. The data obtained were used to calculate k_i/k₀for

carbene 7a with respect to a corresponding alkene by the forꢀ

mula k_i/k₀= (n_i/n₀) (m₀/m_i), where n_i/n₀is the ratio between

the obtained amounts of adducts of carbene 7a with the ith

alkene and with 2ꢀmethylpropene and m₀/m_iis the molar ratio

of 2ꢀmethylpropene to the ith alkene. In each case, the data

from two analogous experiments were averaged. The confiꢀ

dence interval was calculated according to a standard proꢀ

cedure.¹⁷

Reactions of 1,1,1,3ꢀtetrachloroheptane (3b) with bases in

the presence of 2,3ꢀdimethylbutꢀ2ꢀene. A. Using Bu^tOK as a

base. A solution of tetrachloride 3b (400 mg, 1.68 mmol) in

1 mL of hexane was added at ∼20 °C to a mixture of Bu^tOK

(1120 mg, 10 mmol) and 2,3ꢀdimethylbutꢀ2ꢀene (420 mg,

5 mmol) in 5 mL of hexane. The reaction mixture was stirred at

∼20 °C for 48 h and then treated with water. The organic layer

was separated, and the organic material was extracted from the

aqueous phase with ether (3×10 mL). The combined organic

layers were dried with magnesium sulfate, and the solvent was

evaporated. Vacuum microdistillation (10 Torr, bath temperaꢀ

ture 120—130 °C) of the residue gave a 4 : 1 mixture of isoꢀ

meric cyclopropanes 8d and 13 (170 mg, a total yield of 50%).

The spectral characteristics of products 8d and 13 are given in

Tables 4—8.

B. Using KOH as a base. A solution of tetrachloride 3b

(800 mg, 3.36 mmol) in 1 mL of CH₂Cl₂was added to a

mixture of KOH (2.8 g, 50 mmol), one drop of water, BTEAC

(50 mg, 0.22 mmol), 2,3ꢀdimethylbutꢀ2ꢀene (840 mg, 10 mmol),

and CH₂Cl₂(10 mL). The reaction mixture was stirred at ∼20 °C

for 80 h (monitoring by GLC) and then treated with water. The

organic layer was separated, and the organic material was exꢀ

tracted from the aqueous phase with ether (3×10 mL). The

combined organic layers were dried with magnesium sulfate,

and the solvent was evaporated. Vacuum microdistillation

(10 Torr, bath temperature 120—130 °C) of the residue gave a

1.1 : 1 mixture of isomeric cyclopropanes 8d and 13 (325 mg, a

total yield of 48%). The spectral characteristics of products 8d

and 13 are given in Tables 4—8.

Synthesis of 1ꢀbromoꢀ1ꢀ(phenylethynyl)cyclopropanes

(12a,d,e) by the reactions of 1,1,1,3ꢀtetrabromoꢀ3ꢀphenylpropane

(4a) with Bu^tOK in the presence of alkenes. A solution of

tetrabromide 4a (4.36 g, 10 mmol) in 10 mL of benzene was

added at ∼20 °C to a mixture of Bu^tOK (5.6 g, 50 mmol) and a

starting alkene (30 mmol) in 30 mL of benzene. The reaction

mixture was stirred at ∼20 °C for 1 h and then treated with

water. The organic layer was separated, and the organic mateꢀ

rial was extracted from the aqueous phase with benzene

(2×30 mL). The combined organic layers were dried with magꢀ

nesium sulfate, and the solvent was evaporated. The resiꢀ

due was passed through an SiO₂layer in hexane cooled to

–10 °C, and the solvent was removed in vacuo (30—40 °C,

10—15 Torr).

The k_i/k₀value for cisꢀbutene was determined in a separate

experiment. In this case, the starting mixture was prepared by

evaporation—condensation of cisꢀbutene and 2ꢀmethylpropene

after each other into a reaction flask cooled to –20 to –10 °C.

With 2,3ꢀdimethylbutꢀ2ꢀene as the alkene, the residue conꢀ

tained, along with cyclopropane 12a, vinylidenecyclopropane

1252

Russ.Chem.Bull., Int.Ed., Vol. 51, No. 7, July, 2002

Shavrin et al.

14a (8%); in the case of 2ꢀmethylpropene, cyclopropane 12d

was accompanied by vinylidenecyclopropane 14d (11%) (NMR

and GLC data). Product 12a was isolated by recrystallization

from methanol, while cyclopropanes 12d,e were purified by

vacuum distillation. The yields, boiling and melting points,

and the ratios of the transꢀ and cisꢀisomers for products 12a,d,e

are given in Table 2. The spectral characteristics of cycloproꢀ

panes 12a,d,e and 14a,d are presented in Tables 4—7.

Reactions of 3ꢀbromoꢀ1,1,1ꢀtrichloroꢀ3ꢀphenylpropane (2a)

and 1,1,1,3ꢀtetrachloroꢀ3ꢀphenylpropane (3a) with a deficient

amount of Bu^tOK. Potassium tertꢀbutoxide (56 mg, 0.5 mmol)

was added at ∼20 °C to a solution of a starting tetrahalide (2a or

3a) (1 mmol) in 5 mL of hexane. The reaction mixture was

stirred for 60 min and then passed through a thin layer of silica

gel; the sorbent was washed with hexane. After the solvent was

evaporated, the residue contained the starting tetrahalide and

1,1,3ꢀtrichloroꢀ3ꢀphenylpropꢀ1ꢀene (19a) in the ∼1 : 1 ratio

(GLC and NMR data). The latter was identified by comparing

Reactions of 3ꢀsubstituted 1,1,1,3ꢀtetrabromopropanes 4b,c,f

with Bu^tOK in the presence of alkenes. A solution of a starting

tetrahalide (2 mmol) in 1 mL of a solvent specified in Table 2

was added at ∼20 °C to a mixture of Bu^tOK (1350 mg, 12 mmol)

and a starting alkene (6 mmol) in 5 mL of the same solvent.

The reaction mixture was stirred (the reaction duration and

temperature are given in Table 2) until the reaction was comꢀ

pleted (monitoring by GLC). Then the reaction mixture was

treated with water, and the organic layer was separated. The

organic material was extracted from the aqueous phase with

ether (3×10 mL). The combined organic layers were dried with

magnesium sulfate and the solvent was evaporated. A mixture

of the reaction products was isolated from the residue by vacuum

distillation, recrystallization from methanol, or by column chroꢀ

matography in hexane. When compounds 4c,f were used, the

resulting mixtures contained two components, namely, broꢀ

mides 12b,c and 14b,c; with 1,1,1,3ꢀtetrabromoheptane (4b) as

the starting reagent, 1ꢀbromoꢀ1ꢀ(transꢀhexꢀ1ꢀenyl)ꢀ2,2ꢀdiꢀ

methylcyclopropane (17) was detected along with bromides 12f

1

its H and ¹³C NMR spectra with those of an authentic sample

(see below).

Synthesis of 1,1,3ꢀtrichloroꢀ3ꢀphenylpropꢀ1ꢀene (19a).

A mixture of tetrahalide 2a (2.5 g, 8.2 mmol) and triethylamine

(3.3 g, 33 mmol) was refluxed for 8 h. The reaction mixture was

diluted with 20 mL of Et₂O and washed with aqueous 5% HCl.

The organic material was additionally extracted from the aqueꢀ

ous layer with ether (10 mL). The combined organic layers

were dried with magnesium sulfate, and the solvent was evapoꢀ

rated. Vacuum distillation of the residue gave product 19a (0.5 g,

1

28%), b.p. 92—93 °C (2 Torr). H NMR, δ: 5.72 (d, 1 H, CH,

J = 10.2 Hz); 6.30 (d, 1 H, CH, J = 10.2 Hz); 7.20—7.50 (m,

5 H, Ph). ¹³C NMR, δ: 58.4 (CHCl); 124.2 (=CCl₂); 126.9,

128.8, 128.9, 129.4 (Ph, —CH=); 138.4 (C(1), Ph). MS, m/z:

185, 187 [M – Cl]⁺.

Synthesis of 1ꢀchloroꢀ2,2,3,3ꢀtetramethylꢀ1ꢀ(phenylꢀ

ethynyl)cyclopropane (8a) from 1,1,3ꢀtrichloroꢀ3ꢀphenylpropꢀ

1ꢀene (19a). Chloride 19a (152 mg, 0.687 mmol) was added at

∼20 °C to a mixture of 2,3ꢀdimethylbutꢀ2ꢀene (290 mg,

3.4 mmol), Bu^tOK (310 mg, 2.74 mmol), and dodecane (100 mg)

in 3 mL of hexane. Approximately two minutes after the addiꢀ

tion was completed, the reaction mixture contained, along with

the starting trichloride and cyclopropane 8a, allene 22a and

alkyne 21a in the 1 : 1 ratio; their total content was 6% (GLC

data). The latter two compounds were identified by comparing

their retention times with those of authentic samples (see the

section "Reaction of dichloride 21a with a deficient amount of

Bu^tOK"). The reaction mixture was stirred for 30 min and

analyzed by GLC, which showed the complete absence of the

starting trichloride 19a and intermediate compounds 21a and

22a. The yield of cyclopropane 8a was determined from the

ratio of its peak area with that of dodecane with a preꢀcaliꢀ

brated detector. The yield of 8a was 46%.

1

and 14e (GLC and H and ¹³C NMR data). The composition

of the mixtures obtained and the total yields and boiling points

of the reaction products are given in Table 2. The spectral

characteristics of cyclopropanes 12b,c,f and 14b,c,e are preꢀ

sented in Tables 4—8.

1

Compound 17. H NMR, δ: 0.91 (t, 3 H, CH₃in Bu, J =

7.0 Hz); 1.04 (s, 3 H, Me); 1.38 (s, 3 H, Me); 1.20—1.55 (m,

6 H, 3 CH₂); 2.06 (dt, 2 H, —CH₂CH=, J = 6.5 Hz, J =

6.5 Hz); 5.64 (dt, 1 H, —CH₂CH=, J = 15.2 Hz, J = 6.5 Hz);

5.79 (d, 1 H, CBrCH=, J = 15.2 Hz). ¹³C NMR, δ: 14.0

(CH₃CH₂—); 21.4, 22.3, 22.8, 25.1, 26.2, 27.2, 31.3, 31.6

(CMe₂, 2 C(CH₃), 4 CH₂, CBr); 131.3 and 133.6 (CH=CH).

MS, m/z: 230, 232 [M]⁺.

Reaction of 1,1,1,3ꢀtetrabromoꢀ3ꢀphenylpropane (4a) with

KOH in the presence of 2,3ꢀdimethylbutꢀ2ꢀene. A solution of

tetrabromide 4a (1 g, 2.3 mmol) in 1 mL of CH₂Cl₂was added

to a mixture of KOH (1.8 g, 30 mmol), benzyltriethylammoꢀ

nium chloride (50 mg), and 2,3ꢀdimethylbutꢀ2ꢀene (570 mg,

6.8 mmol) in 10 mL of CH₂Cl₂. The reaction mixture was

stirred at ∼20 °C for 2 h. The course of the reaction was moniꢀ

tored by GLC. Then the reaction mixture was treated with

water, and the organic layer was separated. The organic mateꢀ

rial was extracted from the aqueous phase with ether (3×10 mL).

The combined organic layers were dried with magnesium sulꢀ

fate. Column chromatography of the residue on silica gel in

hexane gave a 1.7 : 1 mixture of bromides 14a and 15 (240 mg).

The spectral characteristics of cyclopropane 14a are given in

Tables 7 and 8.

Reactions of 3ꢀbromoꢀ1,1,1ꢀtrichloroheptane (2b) and

1,1,1,3ꢀtetrachloroheptane (3b) with a deficient amount of

Bu^tOK. The reactions were carried out as described above for

the reactions of halides 2a and 3a with Bu^tOK. After being

treated with water, the reaction mixture contained the starting

reagent (∼50%) and products 19c and 20b in the 1 : 3.5 ratio

(for 2b) or products 19b and 20b in the 1 : 1.2 ratio (for 3b)

(NMR and GLC data). The products were identified from the

¹H NMR spectra of the resulting mixtures.

1

Compound 19b. H NMR, δ: 0.91 (t, 3 H, CH₃in Bu, J =

7.0 Hz); 1.20—2.00 (m, 6 H, 3 CH₂); 4.75 (dt, 1 H, CHCl,

J = 11.1 Hz, J = 7.2 Hz); 6.10 (d, 1 H, CH=CCl₂, J = 11.1 Hz).

Compound 19c. ¹H NMR, δ: 0.91 (t, 3 H, CH₃in Bu,

J = 7.0 Hz); 1.20—2.00 (m, 6 H, 3 CH₂); 4.66 (dt, 1 H,

CHBr, J = 11.1 Hz, J = 7.2 Hz); 5.98 (d, 1 H, CH=CCl₂, J =

11.1 Hz).

2,2,3,3ꢀTetramethylꢀ1ꢀ(phenylvinylidene)cyclopropane (15).

¹H NMR, δ: 1.40 (s, 6 H, 2 Me); 1.49 (s, 6 H, 2 Me); 6.20 (s,

1 H, CH=); 7.30—7.60 (m, 5 H, Ph). ¹³C NMR, δ: 21.3 (2 CH₃);

22.0 (2 CH₃); 31.4 (2 CMe₂); 95.8 (=CH—); 99.1

(=C in cycloꢀC₃); 126.4, 127.1, 128.5 (Ph); 136.8 (C(1), Ph);

182.9 (=C=). MS, m/z: 198 [M]⁺.

1

Compound 20b. H NMR, δ: 0.92 (t, 3 H, CH₃in Bu, J =

7.0 Hz); 1.20—1.55 (m, 4 H, 2 CH₂); 2.18 (dt, 2 H, —CH₂CH=,

Generation of (alkꢀ1ꢀynyl)halocarbenes

Russ.Chem.Bull., Int.Ed., Vol. 51, No. 7, July, 2002

1253

J = 7 Hz, J = 6.5 Hz); 6.11 (d, 1 H, CHCCl₃, J = 15.5 Hz);

6.27 (dt, 1 H, CH₂CH=, J = 15.5 Hz, J = 7.2 Hz).

1ꢀBromoꢀ1ꢀfluoroheptꢀ2ꢀyne (27). ¹H NMR, δ: 0.92 (t, 3 H,

CH₃in Bu, J = 7 Hz); 1.20—1.60 (m, 4 H, 2 CH₂); 2.20—2.45

(m, 2 H, CH₂C≡); 6.77 (dt, 1 H, —CHFBr, J_H,F= 52 Hz, J =

1.7 Hz). ¹⁹F NMR, δ (CFCl₃): –121.5 (d, —CHFBr, J =

52 Hz). MS, m/z: 113 [M – Br]⁺.

Reaction of 1,1,3ꢀtribromoꢀ1ꢀfluoroheptane (1b) with Bu^tOK:

identification of intermediate products. Potassium tertꢀbutoxide

(158 mg, 1.41 mmol) was added at ∼20 °C to a solution of

tetrahalide 1b (500 mg, 1.41 mmol) in 5 mL of hexane. The

reaction mixture was stirred for 15 min and then treated with

water. The organic layer was separated, and the organic mateꢀ

rial was extracted from the aqueous phase with ether (3×10 mL).

The combined organic layers were dried with magnesium sulꢀ

fate, and the solvent was evaporated. The residue contained a

mixture of the starting compound 1b, transꢀ1,1ꢀdibromoꢀ1ꢀ

fluoroheptꢀ2ꢀene (24), and isomeric Eꢀ and Zꢀ1,3ꢀdibromoꢀ1ꢀ

fluoroheptꢀ1ꢀenes (25) in the 1 : 1.8 : 0.9 : 0.75 ratio (GLC and

NMR data). The total yield was 340 mg.

This work was financially supported by the Russian

Foundation for Basic Research (Project Nos. 01ꢀ03ꢀ32674

and 00ꢀ15ꢀ97387).

References

1. K. N. Shavrin, V. D. Gvozdev, and O. M. Nefedov, Izv.

Akad. Nauk, Ser. Khim., 1998, 1185 [Russ. Chem. Bull.,

1998, 47, 1154 (Engl. Transl.)].

2. K. N. Shavrin, V. D. Gvozdev, and O. M. Nefedov,

Mendeleev Commun., 1997, 144.

3. K. N. Shavrin, V. D. Gvozdev, and O. M. Nefedov, Izv.

Akad. Nauk, Ser. Khim., 1997, 2079 [Russ. Chem. Bull.,

1997, 46, 1973 (Engl. Transl.)].

4. K. N. Shavrin, V. D. Gvozdev, and O. M. Nefedov, Izv.

Akad. Nauk, Ser. Khim., 1992, 1128 [Bull. Russ. Acad. Sci.,

Div. Chem. Sci., 1992, 41, 885 (Engl. Transl.)].

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Okonnishnikova, I. E. Dolgy, and O. M. Nefedov, J. Chem.

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6. K. N. Shavrin, I. B. Shvedova, and O. M. Nefedov, Izv.

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7. M. S. Kharash, O. Reinmuth, and W. H. Urry, J. Am.

Chem. Soc., 1947, 69, 1105.

Compound 24. ¹H NMR, δ: 0.88 (t, 3 H, CH₃in Bu,

J = 7 Hz); 1.20—1.55 (m, 4 H, 2 CH₂); 2.06 (dt, 2 H,

—CH₂CH=, J = 7 Hz, J = 6.5 Hz); 5.85—6.15 (m, 2 H,

—CH=CH—). ¹⁹F NMR, δ (CFCl₃): –51.8 (d, CFBr₂, J =

16.6 Hz). MS, m/z: 193, 195 [M – Br]⁺.

Compound Eꢀ25. ¹H NMR, δ: 0.88 (t, 3 H, CH₃in Bu,

J = 7 Hz); 1.20—2.00 (m, 6 H, 3 CH₂); 4.72 (dt, 1 H, CHBr,

J = 11.1 Hz, J = 7.2 Hz); 5.31 (dd, 1 H, CH=CFBr, J =

11.1 Hz, J_H,F= 27.9 Hz). ¹⁹F NMR, δ (CFCl₃): –69.2 (d,

=CFBr, J = 27.9 Hz). MS, m/z: 193, 195 [M – Br]⁺.

Compound Zꢀ25. ¹H NMR, δ: 0.88 (t, 3 H, CH₃in Bu,

J = 7 Hz); 1.20—2.00 (m, 6 H, 3 CH₂); 4.48 (dtd, 1 H, CHBr,

J = 10.9 Hz, J = 7.1 Hz, J_H,F= 2.5 Hz); 5.71 (dd, 1 H,

CH=CFBr, J = 10.9 Hz, J_H,F= 10.9 Hz). ¹⁹F NMR, δ (CFCl₃):

–68.3 (dd, =CFBr, J = 10.9 Hz, J = 2.5 Hz). MS, m/z: 193,

195 [M – Br]⁺.

The mixture of the halides obtained (340 mg) was dissolved

in 5 mL of hexane, and Bu^tOK (120 mg, 1.07 mmol) was added

at ∼20 °C. After 30 min, the starting tetrahalide 1b was comꢀ

pletely consumed (GLC data), and the reaction gave, along

with trihalides 24 and 25, two new products identified as

dihalides 26 and 27 in 12 and 5% yields, respectively. After

60 min, the reaction mixture contained transꢀ24 (45%), the

Eꢀisomer of 25 (25%), the Zꢀisomer of 25 (3%), allene 26

(15%), and alkyne 27 (5.5%) (GLC data). When the mixture

reacted with Bu^tOK for 90 min, the relative content of prodꢀ

ucts 26 and 27 decreased to 12 and 5%, respectively. The reacꢀ

tion mixture was treated with water. The organic layer was

separated, and the organic material was extracted from the

aqueous phase with ether (3×10 mL). The combined organic

layers were dried with magnesium sulfate, and the solvent was

evaporated in vacuo at a bath temperature of no higher than

40 °C. The residue (164 mg) was analyzed by NMR spectrosꢀ

copy and GLꢀMS spectrometry.

8. M. Asscher and D. Vosfi, J. Chem. Soc., 1963, 1887.

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to, 1972.

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Sugimoto Kikuo, Fujimoto Tamotsu, Takashima Toshiyuki,

and Kondo Kiyosi, Bull. Chem. Soc. Jpn., 1986, 59, 221.

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Weyl), Stuttgart, Georg Thieme, 1989, B. E19b, Teil 1, 138.

14. A. Roedig, in Methoden der organischen Chemie (Houbenꢀ

Weyl), Stuttgart, Georg Thieme, 1960, B. V/4, 773.

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J. Wiley and Sons, New York—London—Sydney—Toronꢀ

to, 1972.

1ꢀBromoꢀ1ꢀfluoroheptaꢀ1,2ꢀdiene (26). ¹H NMR, δ: 0.92

(t, 3 H, CH₃in Bu, J = 7 Hz); 1.20—1.60 (m, 4 H, 2 CH₂);

2.20—2.45 (m, 2 H, CH₂CH=); 5.97 (dt, 1 H, —CH=, J =

6.5 Hz, J_H,F= 1.6 Hz). ¹⁹F NMR, δ (CFCl₃): –95.4 (d, =CFBr,

J = 1.6 Hz). MS, m/z: 150, 152 [M – C₃H₆]⁺.

Received December 21, 2001;

in revised form March 14, 2002

Article Doi

Alkynylhalocarbenes 4. Generation of (alk-1-ynyl)halocarbenes from 3-substituted 1,1,1,3-tetrahalopropanes under the action of bases

DOI: 10.1023/A:1020952513679

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