Photochemical Radical C-H Halogenation of Benzyl N-Methyliminodiacetyl (MIDA) Boronates: Synthesis of α-Functionalized Alkyl Boronates

alpha-Haloboronates are useful organic synthons that can be converted to a diverse array of alpha-substituted alkyl borons. Methods to alpha-haloboronates are limiting and often suffer from harsh reaction conditions. Reported herein is a photochemical radical C-H halogenation of benzyl N-methyliminodiacetyl (MIDA) boronates. Fluorination, chlorination, and bromination reactions were effective by using this protocol. Upon reaction with different nucleophiles, the C-Br bond in the brominated product could be readily transformed to a series of C-C, C-O, C-N, C-S, C-P, and C-I bonds, some of which are difficult to forge with alpha-halo sp(2)-B boronate esters. An activation effect of B(MIDA) moiety was found.

Automated summary

A new method was proposed utilizing benzyl N-methyliminodiacetyl (MIDA) boronates for photochemical radical C-H halogenation, enabling successful fluorination, chlorination, and bromination reactions. The resulting brominated product could be further transformed into a variety of organic compounds, including those difficult to form with alpha-halo sp(2)-B boronate esters, by reaction with different nucleophiles. An activation effect of the B(MIDA) moiety was discovered.