Synthesis
N-Allyl-N-formyl-4-methylbenzenesulfonamide (4a). n-Butyl
lithium (1.64 M in hexane, 500 lL, 0.81 mmol) was added at
0 ¡C to a solution of N-allyl-4-methylbenzenesulfonamide (156
mg, 0.74 mmol) in THF (4 mL). After stirring for 5 min a
solution of N-formylbenzotriazole11 (130 mg, 0.89 mmol) in
THF (0.5 mL) was added. After stirring for 1 h at room tem-
perature tert-butyl methyl ether (15 mL) was added and the
methyl ether (3 ] 15 mL). The combined organic phases were
dried (Na SO ) and concentrated. The residue was Ðltered
2
4
over a 2 cm layer of silica gel (previously deactivated with
triethylamine) using pentaneÈtert-butyl methyl ether (10 : 1)
containing 1% triethylamine. This furnished compound 7a as
a slightly yellowish solid that was used as obtained in the next
step. 1H NMR (300 MHz, CDCl ): d 1.26 (s, 12 H), 2.42 (s, 3
3
H), 4.03 (m, 2 H), 4.46 (d, J \ 16.2, 1 H), 5.00È5.19 (m, 2 H),
5.58 (ddt, J \ 17.3, 10.4 and 5.2, 1 H), 7.30 (m, 2 H), 7.61 (d,
solution was extracted with saturated aqueous NaHCO solu-
J \ 16.1 Hz, 1 H), 7.70 (m, 2 H). 13C NMR (75 MHz, CDCl ):
3
3
tion (15 mL). The aqueous phase was extracted with tert-butyl
d 21.5, 24.7, 47.4, 83.0, 118.1, 127.1, 129.8, 131.0, 136.3, 142.7,
methyl ether (3 ] 15 mL) and the combined organic phases
144.0.
were dried (Na SO ) and concentrated. Flash chromatog-
2
4
raphy of the residue with pentaneÈtert-butyl methyl ether
N-Allyl-4-methyl-N-[(E)-3-(4,4,5,5-tetramethyl[1,3,2]dioxa-
borolan-2-yl)-propenyl]-4-benzenesulfonamide (8a). A solution
of compound 7a (540 mg, 1.48 mmol) and chloroiodomethane
(140 lL, 1.92 mmol) in THF (7.5 mL) was cooled to [100 ¡C.
n-Butyllithium (1.54 M in hexane, 1.25 mL, 1.92 mmol) was
added dropwise and the mixture was allowed to reach room
temperature over 12 h. tert-Butyl methyl ether (20 mL) was
added and the mixture was extracted with pH 7 bu†er solu-
tion (15 mL). The aqueous phase was extracted with tert-butyl
methyl ether (3 ] 15 mL). The combined organic phases were
dried (Na SO ) and concentrated. The residue was Ðltered
(5 : 1) furnished compound 4a (165 mg, 93%) as a colorless
crystalline solid of m.p. 43 ¡C. 1H NMR (300 MHz, CDCl ): d
3
2.46 (s, 3 H), 4.11 (dt, J \ 6.0 and 1.3, 2 H), 5.08 (dq, J \ 10.2
and 1.0, 1 H), 5.15 (dq, J \ 17.2 and 1.0, 1 H), 5.60 (ddt,
J \ 17.0, 10.3 and 6.0 Hz, 1 H), 7.36 (m, 2 H), 7.74 (m, 2 H),
9.11 (s, 1 H). 13C NMR (75 MHz, CDCl ): d 21.6, 44.6, 119.0,
3
127.5, 130.2, 130.7, 135.2, 145.5, 160.9. C
H
NO S requires:
11 13
3
C 55.21, H 5.48, N 5.85; found: C 55.06, H 5.21, N 5.81%.
N-Allyl-N-(2,2-dichlorovinyl)-4-methylbenzenesulfonamide
(5a). Compound 4a (940 mg, 3.93 mmol) and tri-
phenylphosphine (3.09 g, 11.8 mmol) were heated in THF (40
2
4
over a 2 cm layer of silica gel (previously deactivated with
triethylamine) using pentaneÈtert-butyl methyl ether (6 : 1)
containing 1% triethylamine. This furnished compound 8a
(450 mg, 74%) as a slightly yellowish oil that was used as
mL) to 55 ¡C. CCl (3.8 mL, 39 mmol) was added dropwise
4
over 4 h. After cooling to room temperature tert-butyl methyl
ether (40 mL) was added and the solution was extracted with
saturated aqueous NaHCO solution (40 mL). The aqueous
obtained in the next step. 1H NMR (300 MHz, CDCl ): d 1.23
3
3
phase was extracted with tert-butyl methyl ether (3 ] 30 mL).
(s, 12 H), 1.62 (m, 2 H), 2.41 (s, 3 H), 3.95 (m, 2 H), 4.90 (dt,
The combined organic phases were dried (Na SO ) and con-
J \ 14.2 and 7.4, 1 H), 5.08È5.22 (m, 2 H), 5.65 (ddt, J \ 17.2,
2
4
centrated. Flash chromatography of the residue with pentaneÈ
tert-butyl methyl ether (10 : 1) furnished 5a (1.17 g, 97%) as a
colorless crystalline solid of m.p. 90 ¡C. 1H NMR (300 MHz,
10.3 and 5.4, 1 H), 6.52 (dt, J \ 14.2 and 1.3 Hz, 1 H), 7.28 (m,
2 H), 7.68 (m, 2 H). 13C NMR (75 MHz, CDCl ): d 21.5, 24.8,
3
48.4, 83.3, 109.3, 117.6, 125.7, 127.1, 29.5, 132.1, 136.5, 143.3.
CDCl ): d 2.43 (s, 3 H), 4.00 (d, J \ 6.3, 2 H), 5.15 (dq,
3
J \ 10.0 and 1.0, 1 H), 5.18 (dq, J \ 17.1 and 1.2, 1 H), 5.68
(4aR*,8aS*)-5-(Toluene-4-sulfonyl)octahydropyrano[3,2-b]-
pyridin-2-one (13a). Biphephos17 (17.3 mg, 0.022 mmol) was
added to a solution of dicarbonyl rhodium acetylacetonate
(2.8 mg, 0.011 mmol) in THF (2 mL). After stirring for 10 min
a solution of compound 8a (415 mg, 1.10 mmol) in THF (4
mL) was added. This mixture was transferred to an autoclave,
adding THF (4 mL) in the transfer. The autoclave was heated
(ddt, J \ 17.0, 10.2 and 6.3 Hz, 1 H), 6.31 (s, 1 H), 7.32 (m, 2
H), 7.69 (m, 2 H). 13C NMR (75 MHz, CDCl ): d 21.6, 51.7,
3
119.4, 124.3, 124.8, 127.4, 129.9, 131.9, 135.7, 144.2.
C
H
Cl NO S requires: C 47.07, H 4.28, N 4.57; found: C
12 13
2
2
47.01, H 4.27, N 4.45%.
N-Allyl-N-ethynyl-4-methylbenzenesulfonamide (6a). n-Butyl
lithium (1.53 M in hexane, 5.4 mL, 8.3 mmol) was added drop-
wise at [78 ¡C to a solution of compound 5a (1.16 g, 3.78
mmol) in THF (19 mL). After stirring for 30 min the mixture
was allowed to reach [20 ¡C over 2 h. Methanol (0.77 mL, 19
mmol) and tert-butyl methyl ether (30 mL) were added. The
to 60 ¡C for 4 days under 5 bar of COÈH (1 : 1). The contents
2
were diluted with tert-butyl methyl ether (20 mL) and the
mixture was extracted with saturated aqueous NaHCO solu-
3
tion (15 mL). The aqueous phase was extracted with tert-butyl
methyl ether (3 ] 15 mL). The combined organic phases were
dried (Na SO ) and concentrated. Flash chromatography of
mixture was extracted with saturated aqueous NaHCO solu-
2
4
3
the residue over silica gel using CH Cl Ètert-butyl methyl
tion (30 mL). The aqueous phase was extracted with tert-butyl
2
2
ether (3 : 1) furnished a 1 : 1 anomeric mixture of compound
12a (274 mg, 80%) as a colorless oil.
methyl ether (3 ] 20 mL). The combined organic phases were
dried (Na SO ) and concentrated. Flash chromatography of
2
4
An aliquot of this mixture (100 mg, 1.32 mmol) was taken
up in dichloromethane (1 mL). N-Methylmorpholine N-oxide
(56 mg, 0.48 mmol), powdered molecular sieves (4 A, 116 mg)
and tetrapropylammonium perruthenate (5.6 mg, 0.016 mmol)
were added. After stirring for 1 h at room temperature the
mixture was Ðltered over a 2 cm layer of silica gel using
CH Cl Ètert-butyl methyl ether (4 : 1) and the solution was
the residue over alumina (basic) with pentaneÈtert-butyl
methyl ether (5 : 1) furnished compound 6a (721 mg, 81%) as a
slightly yellowish solid of m.p. 70 ¡C. 1H NMR (300 MHz,
CDCl ): d 2.37 (s, 3 H), 2.65 (s, 1 H), 3.88 (dt, J \ 6.2 and 1.2,
3
2 H), 5.11È5.24 (m, 2 H), 5.66 (ddt, J \ 17.1, 10.1 and 6.3 Hz, 1
H), 7.29 (m, 2 H), 7.74 (m, 2 H). 13C NMR (75 MHz, CDCl ):
3
d 21.5, 53.9, 59.2, 75.8, 120.0, 127.7, 129.7, 130.5, 134.6, 144.8.
2
2
concentrated. Flash chromatography of the residue over silica
gel with pentaneÈethyl acetate (1 : 1) furnished compound 13a
(77 mg, 78%) as a colorless crystalline solid of m.p. 152 ¡C. 1H
NMR (500 MHz, C D ): d 0.85 (tdd, J \ 13.1, 11.5 and 4.5, 1
C
H
NO S requires: C 61.25, H 5.57, N 5.95; found: C
12 13
2
61.35, H 5.41, N 5.89%.
N-Allyl-4-methyl-N-[(E)-2-(4,4,5,5-tetramethyl[1,3,2]dioxa-
borolan-2-yl)-vinyl]benzenesulfonamide (7a). Pinacolborane13
(269 mg, 2.1 mmol) and zirconocene hydridochloride (51 mg,
0.2 mmol) were added to a solution of compound 6a (471 mg,
2 mmol) in dichloromethane (1 mL). After 8 h at room tem-
perature tert-butyl methyl ether (20 mL) was added and the
6
6
H). 1.06È1.13 (m, 1 H), 1.21 (ttd, J \ 13.6, 12.3 and 4.0, 1 H),
1.66 (m, 1 H), 1.90È2.11 (m, 4 H), 1.97 (s, 3 H), 2.17È2.25 (m, 2
H), 3.47 (ddd, J \ 11.4, 9.0 and 4.7, 1 H), 3.93 (ddd, J \ 12.1,
4.0 and 2.9 Hz, 1 H), 6.84 (m, 2 H), 7.52 (m, 2 H). 13C NMR
(125 MHz, C D ): d 21.1, 22.8, 25.1, 28.5, 30.6, 49.2, 58.5, 78.0,
6
6
mixture was extracted with saturated aqueous NaHCO solu-
127.6, 129.7, 136.2, 143.3, 167.9. C
H
NO S requires: C
3
15 19
4
tion (10 mL). The aqueous phase was extracted with tert-butyl
58.23, H 6.19, N 4.53; found: C 58.10, H 6.11, N 4.66%.
New J. Chem., 2001, 25, 369È373
371