The Aza-Boron-Wittig Reaction: Stereoselective Synthesis of Vinyl Boronates from Amides and Lactams

Keywords

amides - aza-boron-Wittig reaction - iridium catalysis - lactams - vinyl boronates

Significance

The boron-Wittig reaction is a well-established method for synthesizing olefins from carbonyls and boron-stabilized carbanions. To date, extension of this methodology to include imines has remained elusive, largely due to the weak bond formed between boron and nitrogen. The authors herein disclosed a catalytic reductive protocol to overcome these difficulties, thereby providing the first methodology for an aza-boron-Wittig reaction.

Comment

The main advantage of the reductive aza-boron-Wittig reaction over a typical boron-Wittig reaction is the very high observed E/Z selectivity. For instance, benzaldehyde was reacted with 1,1-diborylalkane under standard boron-Wittig conditions to afford an E/Z ratio of 9.6:1. The same product is formed under the reported conditions with an E/Z ratio of > 99:1.

Publication History

Article published online:
22 May 2025