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Enantioselective Phase‐Transfer Catalytic α‐Benzylation and α‐Allylation of α‐ tert ‐Butoxycarbonyllactones
Author(s) -
Ha Min Woo,
Lee Heejin,
Yi Hye Yeong,
Park Yohan,
Kim Sori,
Hong Suckchang,
Lee Myungmo,
Kim Mihyun,
Kim TaekSoo,
Park Hyeunggeun
Publication year - 2013
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201200976
Subject(s) - chemistry , enantioselective synthesis , catalysis , toluene , alkyl , bromide , organic chemistry , phase transfer catalyst , hydroxide , medicinal chemistry , alkylation , phase (matter)
A new enantioselective α‐benzylation and α‐allylation of α‐ tert ‐butoxycarbonyllactones was devloped. α‐Benzylation and α‐allylation of α‐ tert ‐butoxycarbonylbutyrolactone and α‐ tert ‐butoxycarbonylvalerolactone under phase‐transfer catalytic conditions (50% cesium hydroxide, toluene, −60 °C) in the presence of ( S , S )‐3,4,5‐trifluorophenyl‐NAS bromide (1 mol%) afforded the corresponding α‐substituted α‐ tert ‐butoxycarbonyllactones in very high chemical yields (up to 99%) and optical yields (up to 99% ee ). The synthetic potential of this method has been successfully demonstrated by the asymmetric synthesis of unnatural α‐quaternary homoserines, 3‐alkyl‐3‐carboxypyrrolidine and 3‐alkyl‐3‐carboxypiperidine.