Enantioselective Iridium(I)-Catalyzed Allylation of Sodium 2-Aminobenzenethiolates

Key words

iridium - allylation - N,S-heterocycles

Significance

Iridium-catalyzed enantioselective allylation has emerged as a powerful method to synthesize structurally diverse, chiral molecules. Despite much progress in the area of enantio­selective carbon–sulfur bond formation using ­iridium, there have been no reports on the use of sodium 2-aminobenzenethiolate as a nucleophile in this class of reaction. Despite, the potential of this substrate class to encounter detrimental ‘ortho-substituent effects’ on stereoselectivity, Zhao accomplishes selective and highly enantioselective S-allylation.

Comment

The authors report an iridium-catalyzed asymmetric S-allylation reaction using chiral phosphoramidite ligands. The method is highly regio- and enantioselective for a variety of aryl- and alkyl-substituted allyl carbonates. Yields range from moderate to good with excellent enantiocontrol. In most cases, the authors are able to completely inhibit bisallylation and maintain high levels of branched-to-linear selectivity. The author use the products to synthesize enantioenriched N,S-heterocycles via an N-allylation/ring-closing metathesis sequence.