A new chiral oxazoline derived from camphor and its conversion to (R)-2-methylalkanoic acids
作者:Sosale Chandrasekhar、Amina Kausar
DOI:10.1016/s0957-4166(00)00197-x
日期:2000.6
(1S,5R,7R)-(-)-10, 10-Dimethyl-3-ethyl-4-oxa-2-azatricyclo[5.2.1.0(1,5)]dec-2-ene 2 was prepared in 95% yield from (1S)-1-amino-2-exo-hydroxyapocamphane 1. The chiral oxazoline could be alkylated (LDA/THF/-78 degrees C/RX, RX = ethyl, n-propyl, n-butyl iodides or benzyl bromide) to 3 in 95% yield and > 95% diastereoselectivity, and the products hydrolysed to (R)-2-methylalkanoic acids 4 (43-47% yield, 93-98% e.e.). (C) 2000 Elsevier Science Ltd. All rights reserved.
(**1S**,5**R**,7**R**)-(-)-10,10-二甲基-3-乙基-4-氧杂-2-氮杂三环[5.2.1.0(1,5)]癸-2-烯**2**由(**1S**)-1-氨基-2-外-羟基阿朴卡品-**1**以95%的收率制得。该手性环氧化物能够在LDA/THF/-78℃条件下与碘化物或溴化物(RX = 乙基碘化物、正丙基碘化物、正丁基碘化物或苄基溴化物)发生烷基化反应,以95%的收率和>95%的对映选择性得到**3**。将**3**水解可得(**R**)-2-甲基烷酸**4**,其收率为43-47%,对映体过量为93-98%。© 2000 Elsevier Science Ltd. 保留所有权利。