Asymmetric synthesis of chiral beta-amiNo acids

摘要

The invention herein is directed to a process for the preparation of ethyl 3S-amino-4-pentynoate which involves treating 3- (trimethylsilyl)-2- propynal with L-phenylglycinol in toluene to produce . alpha.S-[[3- (trimethylsilyl)-2-propynylidene amino]benzenethanol; reacting S- [[3-(trimethylsilyl)-2- propynylidene]amino] benzenethanol with BrZnCH.sub. 2 CO.sub.2 t-Bu in THF/NMP to produce 1,1- dimethylethyl 3S-[(2-hydroxy-1S- phenylethyl)amino]-5-(trimethylsilyl)-4- pentynoate; reacting the 1,1- dimethylethyl 3S-[(2-hydroxy-1S-phenylethyl) amino]-5-(trimethylsilyl)-4- pentynoate with sodium periodate to form 1,1- dimethylethyl 3S- [(phenylmethylene)amino]-5-(trimethylsilyl)-4- pentynoate; hydrolyzing 1, 1-dimethylethyl 3S-[(phenylmethylene)amino]-5- (trimethylsilyl)-4- pentynoate to produce 1,1-dimethylethyl 3S-amino-5- (trimethylsilyl)-4- pentynoate; transesterifying 1,1-dimethyl 3S-amino-5- (trimethylsilyl)-4- pentynoate and desilylating to produce ethyl 3S-amino- 4-pentynoate.