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Base‐Induced Sequential Cyclization–Rearrangement of Enantioenriched 3‐Aminoalkanoates to Five‐ and Seven‐Membered Lactams
Author(s) -
Sakai Takeo,
Yamada Kenichi,
Tomioka Kiyoshi
Publication year - 2008
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.200700423
Subject(s) - stereochemistry , lactam , chirality (physics) , chemistry , beta lactam , chiral symmetry , physics , biochemistry , quantum mechanics , nambu–jona lasinio model , quark , antibiotics
Abstract By treatment with t BuLi, linear 3‐aminoalkanoates ( 4 ) were converted stereoselectively into five‐ and seven‐membered lactams ( trans‐ 5 and cis‐ 6 ). Initial cyclization to azetidin‐2‐one with subsequent aza‐[1,2] and [2,3] rearrangement is the probable mechanistic pathway from 4 to 5 and 6 . Although enantioenriched 4 was converted into nearly racemic 5 and 6 , a linear 3‐amino‐2‐methylalkanoate ( 17 ) with 90 % ee bearing chirality at the ester α‐position afforded an all‐ cis seven‐membered lactam ( 18 ) bearing three asymmetric centers with 85 % ee .