Stereoselective control in the Staudinger reactions involving monosubstituted ketenes with electron acceptor substituents: experimental investigation and theoretical rationalization
Stereoselective C-3 alkylation of trans-3-phenylsulfonyl-β-lactams with organic halides to access C-3 substituted β-lactams using sulfonyl moiety as an activating group
protocol for the C-3 alkylation of trans-3-phenylsulfonyl-β-lactams 6(a-e) with active organic halides in presence of K2CO3 as mild base and DMF as solvent is described. This protocol furnished cis- and trans-β-lactams as major and minor isomers respectively with alkyl halides while arylalkyl/unsaturated halides yield only cis-β-lactams exclusively. Further, the effect of sterically bulky group on the
描述了在以K 2 CO 3为弱碱和以DMF为溶剂的条件下,用活性有机卤化物对反式-3-苯基磺酰基-β-内酰胺6(ae)进行C-3烷基化的磺酰基促进合成方案。该方案分别将顺式和反式-β-内酰胺作为主要和次要异构体提供了烷基卤,而芳基烷基/不饱和卤化物仅仅产生顺式-β-内酰胺。此外,通过使3-苯基磺酰基-β-内酰胺6(de)与巴豆酰氯(主要为E)反应,获得β-内酰胺的非对映异构混合物,研究了空间大基团对C-3取代的影响。7 / 7ʹ和8。该策略在成本效益,功能组容忍度和操作简便性方面显示出优势。
Simple Approach to β-Lactam Derivatives from <i>N</i>-Acylimidazoles
作者:Moshe Nahmany、Artem Melman
DOI:10.1021/jo0607010
日期:2006.7.1
Reaction of N-acylimidazoles possessing an electron-withdrawing group in the alpha position with diarylimines produces beta-lactams in high yields.