Periselectivity Switch of Acylketenes in Cycloadditions with 1-Azadienes: Microwave-Assisted Diastereoselective Domino Three-Component Synthesis of α-Spiro-δ-lactams

The microwave-assisted Wolff rearrangement of cyclic 2-diazo-1,3-diketones in the presence of primary amines and α,β-unsaturated aldehydes provides a straightforward three-component stereoselective access to a variety of α-spiro-δ-lactams following an imination/Wolff rearrangement/[2 + 4] cycloaddition domino sequence. With aniline derivatives, a complementary aza-Wittig/Wolff rearrangement/[2 + 4] sequence was developed. These reactions feature an unprecedented reactivity of acylketenes as dienophiles in 6π electrocyclic processes.

在伯胺（primary amines）与α,β-不饱和醛（α,β-unsaturated aldehydes）存在的条件下，对环状2-重氮-1,3-二酮（cyclic 2-diazo-1,3-diketones）进行微波辅助沃尔夫重排（Wolff rearrangement），可经由亚胺化/沃尔夫重排/[2+4]环加成串联反应序列，实现多种α-螺环-δ-内酰胺（α-spiro-δ-lactams）的简便三组分立体选择性合成。针对苯胺衍生物（aniline derivatives），我们开发了与之互补的氮杂维蒂希（aza-Wittig）/沃尔夫重排/[2+4]串联反应过程。此类反应的显著特征为：酰基烯酮（acylketenes）作为亲双烯体（dienophiles）在6π电环化过程（6π electrocyclic processes）中展现出前所未有的反应活性。