Stereoselective Synthesis of β-Benzyl-α-alkyl-β-amino Acids from <scp>l</scp>-Aspartic Acid<sup>1</sup>
作者:Masahiko Seki、Toshiaki Shimizu、Kazuo Matsumoto
DOI:10.1021/jo991241w
日期:2000.3.1
benzene or phenyllithium with alpha-amino carboxyl group of L-aspartic acid skeleton. Alkylation of a dianion of 4 with alkyl halides and subsequent hydrogenation afforded anti-disubstituted beta-amino acids 1b and 1c in high stereoselectivities. Complete reversal of the stereoselection was realized by the alkylation of 4-phenyl-3-tert-butoxycarbonylamino-4-butanolide 6 which was obtained in a single
已经开发了从L-天冬氨酸3立体选择性合成β-苄基-α-烷基-β-氨基酸1和2。由L-天冬氨酸3通过苯或苯基锂与L-天冬氨酸骨架的α-氨基羧基的酰化反应制得5-苯基恶唑烷-2-甲基-4-乙酸甲酯4。4的二价阴离子与烷基卤化物的烷基化反应和随后的氢化反应得到高立体选择性的抗二取代的β-氨基酸1b和1c。立体选择的完全逆转通过4-苯基-3-叔丁氧基羰基氨基-4-丁醇化物6的烷基化而实现,所述4-苯基-3-叔丁氧基羰基氨基-4-丁醇化物6是从4中一步获得的。得到syn-二取代的β-氨基酸2a。副产品2b,2c,