S<sub>N</sub>2 Ring Opening of β-Lactones: An Alternative to Catalytic Asymmetric Conjugate Additions
作者:Scott G. Nelson、Zhonghui Wan、Magdalena A. Stan
DOI:10.1021/jo025519n
日期:2002.7.1
Merging catalytic asymmetric acyl halide-aldehyde cyclocondensation (AAC) reactions with ensuing Grignard-mediated ring opening of the derived enantiomerically enriched beta-lactones is presented as a generally useful asymmetric synthesis of beta-disubstituted carboxylic acids. Enantiomerically enriched beta-lactones are subject to efficient S(N)2 ring opening with a variety of copper-modified alkyl
将催化的不对称酰基卤-醛环缩合(AAC)反应与随后的格氏试剂介导的对映体富集的β-内酯的开环合并在一起,是β-二取代羧酸的一种普遍有用的不对称合成方法。对映体富集的β-内酯可通过各种铜修饰的烷基格氏试剂(包括高度分支的亲核试剂)进行有效的S(N)2开环。内酯亲电子体中的相当大的结构变化也是可以容忍的。苯基和乙烯基衍生的有机金属不是用于开环反应的有效亲核试剂。