β-Oxidation of Ynamides into N,O-Acetals by mCPBA: Application in Enantioselective Intermolecular Transacetalization
摘要:
Oxidation of ynamides by mCPBA led to beta-oxygenation and resulted in formation of carbonyl compounds with alpha-N,O-acetal functionality. These N,O-acetals are formed in high yields and can be stored indefinitely at room temperature. Yet, they can be activated by a chiral Bronsted acid and underwent an enantioselective transacetalization into a alpha-N,O-acetal. Subsequent diastereoselective transformations occurred with exceptional selectivity according to Felkin-Anh model.
Iron(<scp>iii</scp>)-catalyzed tandem annulation of indolyl-substituted <i>p</i>-quinone methides with ynamides for the synthesis of cyclopenta[<i>b</i>]indoles
作者:Ke-Yin Yu、Xiao-Min Ge、Yi-Jun Fan、Xiao-Tao Liu、Xue Yang、Yu-Han Yang、Xian-He Zhao、Xian-Tao An、Chun-An Fan
DOI:10.1039/d2cc03252j
日期:——
two-carbon synthon has been explored for the first time in a novel iron(III)-catalyzed tandem annulation. This (2+2) annulation/retro-4π electrocyclization/imino-Nazarov cyclization cascade reaction is characterized by an unusual structural reconstruction of indolyl-substituted p-QMs, leading to an expeditious assembly of synthetically important functionalized cyclopenta[b]indoles.
在新型铁( III )催化的串联环化反应中,首次探索了吲哚基取代的p -QMs作为新型双碳合成子的独特反应性。这种 (2+2) 环化/retro-4π 电环化/亚氨基-纳扎罗夫环化级联反应的特点是对吲哚基取代的p -QM 进行了不寻常的结构重建,从而导致合成重要的官能化环戊二烯[ b ]吲哚的快速组装。