Synthesis 2016; 48(12): 1825-1854
DOI: 10.1055/s-0035-1560437
special topic
© Georg Thieme Verlag Stuttgart · New York

Cyclization of Imides to 2-Azabicycles via Aminoketyl Radicals by Using Samarium(II) Iodide–Water: Reaction Development, Synthetic Scope, and Mechanistic Studies

Shicheng Shi
Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102, USA   Email: michal.szostak@rutgers.edu
,
Roger Lalancette ◊
Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102, USA   Email: michal.szostak@rutgers.edu
,
Michal Szostak*
Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102, USA   Email: michal.szostak@rutgers.edu
› Author Affiliations
Further Information

Publication History

Received: 27 January 2016

Accepted after revision: 01 March 2016

Publication Date:
27 April 2016 (eFirst)

To whom correspondence about crystallographic data should be addressed

Dedicated to Professor Henri Kagan

Abstract

The first highly selective method for direct addition of aminoketyl radicals [R–C(O)NR1R2], generated from five- or six-membered cyclic imides, to nonactivated π-systems by using the SmI2–H2O reagent is reported. The transformation is operationally simple, scalable, and provides access to valuable angular 2-azabicycles containing three contiguous stereocenters with excellent diastereoselectivity (>95:5 dr). The protocol accommodates a wide range of π-acceptors that can be modulated by the alcohol additive used. Notably, the transformation provides the first general method for generation of aminoketyl radicals by a direct electron capture to amide bonds, thus opening new vistas for applications of these underutilized intermediates in a diverse array of open-shell reaction pathways. Systematic studies on the effects of additives, the scope and limitations of the reaction, and the reaction mechanism are reported.

Supporting Information

 
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