One-Pot Synthesis of Highly Substituted <i>N</i>-Fused Heteroaromatic Bicycles from Azole Aldehydes
作者:Victor K. Outlaw、Felipe B. d’Andrea、Craig A. Townsend
DOI:10.1021/ol5036936
日期:2015.4.17
An efficient route to substituted N-fused aromatic heterocycles, including indolizines, imidazo[1,2-a]pyridines, and imidazo[1,5-a]pyridines from azole aldehydes, is reported. Wittig olefination of the aldehydes with fumaronitrile and triethylphosphine affords predominantly E-alkenes that undergo rapid cyclization upon treatment with a mild base. Substituent control of the 1-, 2-, and 3-positions of
报道了从唑醛制备取代的N-稠合芳香杂环的有效途径,包括中氮茚、咪唑并[1,2- a ]吡啶和咪唑并[1,5- a ]吡啶。醛与富马腈和三乙基膦的维蒂希烯化主要提供E-烯烃,其在用弱碱处理后经历快速环化。显示了所得杂芳族双环的 1-、2-和 3-位的取代基控制。或者,可分离的E-烯烃用亲电子试剂进行选择性烷基化,然后原位环化成在6-位额外取代的中氮茚。