Stereoselective reactions. 14. Efficient enantioselective construction of quaternary carbon centers by the sequential dialkylation of (S)-.gamma.-[(trityloxy)methyl]-.gamma.-butyrolactone. Synthesis of optically active .beta.,.beta.-disubstituted .gamma.-butyrolactones

1988 ◽  
Vol 53 (17) ◽  
pp. 4094-4098 ◽  
Author(s):  
Kiyoshi Tomioka ◽  
Youn Sang Cho ◽  
Fuminori Sato ◽  
Kenji Koga
Keyword(s):  
Optically Active ◽  
Quaternary Carbon ◽  
Carbon Centers ◽  
Stereoselective Reactions ◽  
Gamma Butyrolactone

Kinetic resolution of oxime esters with lipases — synthesis of enantiomerically enriched building blocks with quaternary carbon centers and formal total synthesis of perhydro histrionicotoxin

2002 ◽  
Vol 80 (6) ◽  
pp. 686-691 ◽  
Author(s):  
Nicole Diedrichs ◽  
Ralf Krelaus ◽  
Ina Gedrath ◽  
Bernhard Westermann
Keyword(s):  
Substrate Specificity ◽  
Total Synthesis ◽  
Solvent Effects ◽  
Kinetic Resolution ◽  
Building Blocks ◽  
Beckmann Rearrangement ◽  
Optically Active ◽  
Quaternary Carbon ◽  
Carbon Centers

Enantiomerically enriched oximes bearing stereogenic quaternary carbon centers can be obtained by lipase-catalyzed kinetic resolution of oxime esters. Substrate specificity, solvent effects, and the use of different lipases are discussed. Kinetic resolution of butyrylated oximes by lipase PS in the presence of n-butanol gave the best ee-values of both the saponified oxime and the residual oxime ester. Subsequent stereospecific Beckmann rearrangement of an enantiomerically enriched oxime provided lactams, which could be employed for the synthesis of optically active perhydro histrionicotoxin.Key words: oxime, lipase, kinetic resolution, Beckmann rearrangement, perhydro histrionicotoxin.

scholarly journals Construction of Optically Active CF3-Containing Quaternary Carbon Centers via Stereospecific SN2? Reaction.

ChemInform ◽  
2005 ◽  
Vol 36 (12) ◽  
Author(s):  
Mitsuo Kimura ◽  
Takashi Yamazaki ◽  
Tomoya Kitazume ◽  
Toshio Kubota
Keyword(s):  
Optically Active ◽  
Quaternary Carbon ◽  
Carbon Centers ◽  
Sn2 Reaction

Optically active quaternary carbon centers from the photoaddition of chromium-alkoxycarbene complexes and optically active thiazolines

1992 ◽  
Vol 57 (5) ◽  
pp. 1461-1467 ◽  
Author(s):  
Douglas K. Thompson ◽  
Naoki Suzuki ◽  
Louis S. Hegedus ◽  
Yoshitaka Satoh
Keyword(s):  
Optically Active ◽  
Quaternary Carbon ◽  
Carbon Centers

Construction of Optically Active CF3-Containing Quaternary Carbon Centers via Stereospecific SN2‘ Reaction†

2004 ◽  
Vol 6 (25) ◽  
pp. 4651-4654 ◽  
Author(s):  
Mitsuo Kimura ◽  
Takashi Yamazaki ◽  
Tomoya Kitazume ◽  
Toshio Kubota
Keyword(s):  
Optically Active ◽  
Quaternary Carbon ◽  
Carbon Centers ◽  
Sn2 Reaction
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