Semipinacol Rearrangement of <i>Cis</i>-Fused β-Lactam Diols into Keto-Bridged Bicyclic Lactams
作者:Richard S. Grainger、Marie Betou、Louise Male、Mateusz B. Pitak、Simon J. Coles
DOI:10.1021/ol300605y
日期:2012.5.4
rearrangement proceeds with exclusive N-acyl group migration of a β-lactam ring and results in carbonyl functionality at the 7- and bridging 8-position of the bicycle. Precursor ring-fused β-lactam diols are prepared through a sequence of 4-exo trig carbamoyl radical cyclization, regioselective dithiocarbamate group elimination, and dihydroxylation.
在一系列生物活性分子中普遍存在的6-氮杂双环[3.2.1]辛烷环系统是通过利用环状磷烷或亚硫酸盐中间体的新型半频哪醇重排制备的。重排通过β-内酰胺环的排他性N-酰基进行,并在自行车的7位和8位桥位处产生羰基官能度。前体环稠合的β-内酰胺二醇是通过一系列的4- exo trig氨基甲酰基自由基环化,区域选择性二硫代氨基甲酸酯基团消除和二羟基化制备的。