Photoredox‐Catalyzed Site‐Selective α‐C(sp3)−H Alkylation of Primary Amine Derivatives

The synthetic utility of tertiary amines to oxidatively generate α‐amino radicals is well established, however, primary amines remain challenging because of competitive side reactions. This report describes the site‐selective α‐functionalization of primary amine derivatives through the generation of...

Full description

Saved in:
Bibliographic Details
Published in:Angewandte Chemie International Edition 2019-03, Vol.58 (12), p.4002-4006
Main Authors: Ashley, Melissa A., Yamauchi, Chiaki, Chu, John C. K., Otsuka, Shinya, Yorimitsu, Hideki, Rovis, Tomislav
Format: Article
Language:English
Subjects:
Alkenes
Alkylation
Amines
Amino radical
Catalysis
Derivatives
Divergence
Intermediates
photochemistry
Photoredox catalysis
radicals
reaction mechanisms
Selectivity
Side reactions
Sulfonamides
synthetic methods
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The synthetic utility of tertiary amines to oxidatively generate α‐amino radicals is well established, however, primary amines remain challenging because of competitive side reactions. This report describes the site‐selective α‐functionalization of primary amine derivatives through the generation of α‐amino radical intermediates. Employing visible‐light photoredox catalysis, primary sulfonamides are coupled with electron‐deficient alkenes to efficiently and mildly construct C−C bonds. Interestingly, a divergence between intermolecular hydrogen‐atom transfer (HAT) catalysis and intramolecular [1,5] HAT was observed through precise manipulation of the protecting group. This dichotomy was leveraged to achieve excellent α/δ site‐selectivity. By choice: Judicious choice in nitrogen protecting group allows the site‐selective functionalization α to a primary amine. Under photoredox catalysis conditions, a variety of alkene acceptors participate, leading to good yields and excellent selectivities. Tf=trifluoromethanesulfonyl.
ISSN:1433-7851
1521-3773
DOI:10.1002/anie.201812227