The metalation of oxazoles leads to ring opening to the isocyanoenolate that can be O-acylated to give the unsaturated isonitriles. These substances undergo conventional multicomponent reactions. The products of their reactions are readily converted to acyl substitution products by treatment with acid and a nucleophile. These unsaturated isonitriles are notable by their simple preparations and, unusually, their nonoffensive odors.
Pseudo-Seven-Component Double Azido-Ugi Reaction: an Efficient Synthesis of Bistetrazole Derivatives
作者:Irina V. Kutovaya、Danil P. Zarezin、Olga I. Shmatova、Valentine G. Nenajdenko
DOI:10.1002/ejoc.201900662
日期:2019.6.30
Pseudo‐seven‐component double azido‐Ugi reactions were investigated. Compounds bearing two 1,5‐disubstituted tetrazole rings in the structure were obtained by the proposed approach. Bis‐NH‐tetrazoles were synthesized by means of catalytic debenzylation of bis‐N‐benzyltetrazoles.
A fundamentally newreagent space has been discovered for the Castagnoli-Cushman reaction. Cyclic anhydride has been successfully replaced with CDI-activated monoesters of homophthalic acid allowing direct preparation of tetrahydroisoquinolonic esters. Mechanistic studies suggested a new reaction pathway not involving any previously described alkoxyisocoumarines.