Synthesis of Boronic Esters from Organometallic Reagents and Bis(pinacolato)diboron.

Synthesis of alkyl, aryl, and vinyl boronic esters carrying various chiral and achiral diol‐protecting groups were synthesized starting from the corresponding alkyl, aryl, and vinyl lithium or Grignard reagents. Good to excellent yields were obtained for a large range of substrates. The reaction can be conducted in a gram scale to obtain the product over 80 % yield. This approach provides direct access to neopentyl, pinene, and other boronic esters that are difficult to achieve. Using trimethoxyborane or 2‐isopropoxy pinacolboronic ester. Detailed mechanistic studies have been conducted to understand the mechanism behind the formation of boronic ester starting from organometallic reagents. [ABSTRACT FROM AUTHOR]