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Organic Synteses vol 69 - Paquette L.A.

Paquette L.A., Boecman R.K. Organic Synteses vol 69 - John Wiley & Sons, 1990. - 174 p.
ISBN 0-471-54560-0
Download (direct link): organicsynthesesvol691990.pdf
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5. Nakata, T.; Oishi, T. Tetrahedron Lett. 1980, 21,1641.
6. Ito, Y.; Yamaguchi, M. Tetrahedron Lett. 1983, 24, 5385.
7. Fujita, M.; Hiyama, T. J. Am. Chem. Soc. 1985, 107, 8294.
8. Fujita, M.; Hiyama, T. J. Am. Chem. Soc. 1984, 106, 4629.
9. Fujita, M.; Hiyama, T. J. Org. Chem. 1988, 53, 5415.
10. Montgomery, S. H.; Pirrung, M. C.; Heathcock, C. H. Org. Synth. 1985, 63, 99.
11. Canceill, J.; Jacques, J. Bull. Soc. Chim. Fr. 1970, 2180.
12. Ito, Y.; Katsuki, T.; Yamaguchi, M. Tetrahedron Lett. 1985, 26, 4643.
13. Fujita, M.; Hiyama, T. J. Org. Chem. 1988, 53, 5405.
51
TABLE I
ERYTHRO-SELECTIVE REDUCTION OF a-SUBSTITUTED ß-KETO ACID DERIVATIVES WITH PhMe2SiH/H+ REAGENTa
Substrate6 Time, hr Product0 % Yield*1 Threo: . _Erythro8
0 0 OH o
3 Me^S^NEtz 94 2:98
Me Me
O O OH O
'Pr'^Y^'NEtz 20 'Pr^Y^NEtz 89 1:99
Me Me
0 0 OH O
Ph-^Y^N^] 3 Ph'^V^N^ 9 9 1-99
Me ^ Me ^
0 0 OH O
Ph^Y^OMe 3 ph'^Y^'OMe 87 1:>"
Me Me
aCarried out on a 0.5-1.0 mmol-scale at 0°C employing PhMe2SiH (1.2 mol equiv) and CF3COOH (1-2 mL/mmol). bRacemates were employed unless noted. cMajor isomers are shown. dPurified by silica gel chromatography. eThe ratio was determined by 90 or 400 MHz 1H NMR analysis. 'The optically pure substrate was prepared according to a known method: Evans, D. A.; Ennis, M. D.; Le, T.; Mandel, N.; Mandel, G. J. Am. Chem. Soc. 1984, 106, 1154.
52
TABLE II
THREO-SELECTIVE REDUCTION OF 0-KETO AMIDES WITH PhMe2SiH/F- REAGENT a
Substrate
Time hr
Product
% Yield
Erythro
0 0 ,Y-
PIT 'Y NEt2 Me
O O
cr' ' **
o
12
16
OH o
Ph^Y^"NEt2
Me
OH 0
98
86
>99 : 1
99 : 1
0 O
MeO
Me
o
o o
aV^
Me
1 6
22
OH 0
MeO
92
OH 0
NEtj 93
Me
99 : 1
23 : 77
aCarried out on a 0.5-1.0 mmol scale at 0°C employing PhMeaSiH (1.2 mol equiv) and TASF (10 mol %). bRacemates were employed. °Major isomers are shown. dPurified by silica gel chromatography. eThe ratio was determined by 90 or 400 MHz 1H NMR analysis.
53
Appendix
Chemical Abstracts Nomenclature (Collective Index Number); (Registry Number)
erythro-1 -(3-Hydraxy-2-methyl-3-phenylpropanoyl)piperidine: Piperidine, 1-(3-hydroxy-2-methyl-1-oxo-3-phenylpropyl)-, (R*,R*)-(±)- (11); (99114-36-0) 1-(2-Benzoylpropanoyl)piperidine: Piperidine, 1-(2-methyl-1,3-dioxo-3-phenylpropyl)-, (±)- (11); (99114-34-8)
Propanoylpiperidine: Piperidine, 1-propionyl- (8); Piperidine, 1-(1-oxopropyl)- (9); (14045-28-4)
Propanoyi chloride: Propionyl chloride (8); Propanoyl chloride (9); (79-03-8)
Piperidine (8,9); (110-89-4)
Benzoyl chloride (8,9); (98-88-4)
Trifluoroacetic acid: Acetic acid, trifluoro- (8,9); (76-05-1)
Dimethylphenylsilane: Silane, dimethylphenyl- (8,9); (766-77-8)15 Tris(diethylamino)sulfonium difluorotrimethylsilicate: Sulfur (1+), tris(N-ethyl-ethanaminato)-, difluorotrimethylsilicate (1-) (10); (59201-86-4) ?/veo-1-(3-Hydroxy-2-methy-3-phenylpropanoyl)piperidine, (R*,S*)-: Piperidine, 1-(3-hydroxy-2-methyl-1-oxo-3-phenylpropyl)-, (R*,S*)- (+)- (11); (99114-35-9)
1.3-Dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone: 2(1H)-Pyrimidinone, tetrahydro-
1.3-dimethyl- (8,9); (7226-23-5)
Diethylaminotrimethylsilane: Silanamine, N,N-diethyl-1,1,1 -trimethyl- (8,9); (996-50-9) Diethylaminosulfur trifluoride: Sulfur, (diethylaminato)trifluoro- (9); (38078-09-0)
54
ASYMMETRIC SYNTHESIS OF 4,4-DlALKYLCYCLOHEXENONES FROM CHIRAL BICYCLIC LACTAMS: (R)-4-ETHYL-4-ALLYL-2-CYCLOHEXEN-1-ONE
OH ..9
Ph 3 6
O
Submitted by Albert I. Meyers and Daniel Berney.1 Checked by P. B. Madan, A. Schwartz, and David L. Coffen.
1. Procedure
A. Hexahydro-3-(hydroxymethyl)-8a-methyl-2-phenyl[2S,3S,8aR]-5-oxo-5H-oxazolo[3,2-a]pyridine (Bicydic lactam). To a warm solution of (1 S,2S)-(+)-2-amino-1-phenyl-1,3-propanediol (32.4 g, 194 mmol) (Note 1) in toluene (800 mL), 5-oxo-
55
hexanoic acid (25 g, 912 mmol) (Note 2) is added with stirring. The stirred mixture is heated to reflux under argon with azeotropic removal of water for 18 hr. The reaction mixture is cooled, washed with 0.5 N hydrochloric acid (100 mL) and with saturated sodium bicarbonate solution (50 mL), dried over magnesium sulfate, and evaporated to dryness. The residue is crystallized from methylene chloride/hexane in the cold. The crystals are collected by filtration and washed with cold ether to give 35.9-37.2 g (71-74% yield) of the bicyclic lactam in two crops (Note 3).
B. Hexahydro-6-ethyl-3-(hydroxymethyl)-6-allyl-2-phenyl[2S,3S,6S,8aR]-5-oxo-5H~oxazolo[3,2-a]pyridine. In an oven-dried, 500-mL, round-bottomed flask, containing a magnetic stirring bar, is placed 14.4 g (55.2 mmol) of dry bicyclic lactam prepared in Part A. The flask is flushed with argon and filled with 150 mL of anhydrous tetrahydrofuran (Note 4) and then sealed with a rubber septum. The air in the flask is further replaced by argon (Note 5). After dissolution of the bicyclic lactam, the flask is cooled in dry ice/acetone and the solution is stirred while preparing lithium diisopropylamide (LDA).
To an oven-dried, 200-mL, conical flask (Note 6) with air replaced by argon, containing 50 mL of dry tetrahydrofuran (THF) and sealed with a rubber septum, 13.9 g (19.3 mL, 137.4 mmol) of diisopropylamine (Note 7) is added with a syringe. The flask is placed in an ice-water bath. After 15 min, 84 mL (134.4 mmol) of 1.6 M butyllithium in hexane (Note 8) is slowly added with a syringe and with gentle swirling of the flask. The solution is kept for 5 min at this temperature.
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