Synthesis 2022; 54(09): 2165-2174
DOI: 10.1055/a-1710-7256
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Catalytic Amidomethylative [2+2+2] Cycloaddition of Formaldimine and Styrenes toward N-Heterocycles

Hetti Handi Chaminda Lakmal
,
Jacob Istre
,
Xiaolin Qian
,
,
Henry U. Valle
,
Xue Xu
,
Xin Cui
We are grateful for financial support from the National Science Foundation (CAREER: CHE-1945425), the Office of Research and Economic Development, Mississippi State University, and the Department of Chemistry, Mississippi State University.


This paper is dedicated to the 20th anniversary of the Professor Peter Zhang group.

Abstract

Chemo-switchable catalytic [2+2+2] cycloaddition of alkenes with formaldimines is reported. Bis(tosylamido)methane (BTM) and 1,2-ditosyl-1,2-diazetidine (DTD), two bench-stable precursors for highly reactive tosylformaldimine, have been identified to be effective. BTM worked as a selective releaser of the formaldimine for catalytic [2+2+2] reactions toward hexahydropyrimidine products via a presumable ‘imine–alkene–imine’ addition. A unique catalytic retro-[2+2] reaction of DTD was used and has enabled a proposed ‘imine–alkene–alkene’ pathway with high chemoselectivity for the synthesis of 2,4-di­arylpiperidine derivatives. The two alternative processes are catalyzed by the simple and environmentally benign catalysts InCl3 and FeBr2, respectively.

Supporting Information



Publikationsverlauf

Eingereicht: 15. Oktober 2021

Angenommen nach Revision: 01. Dezember 2021

Accepted Manuscript online:
01. Dezember 2021

Artikel online veröffentlicht:
27. Januar 2022

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