Multistep synthesis of complex boronic acids from simple MIDA boronates.
Due to its sensitivity to most synthetic reagents, it is typically necessary to introduce the boronic acid functional group just prior to its utilization. Overcoming this important limitation, we herein report that air- and chromatographically stable MIDA boronates are compatible with a wide range of common reagents which enables the multistep synthesis of complex boronic acid building blocks from simple B-containing starting materials. X-ray and variable temperature NMR studies link the unique stability of MIDA boronates to a kinetic inaccessibility of the potentially reactive boron p-orbital and/or nitrogen lone pair. These findings were collectively harnessed to achieve a short and modular total synthesis of (+)-crocacin C via the iterative cross-coupling of a structurally complex, MIDA-protected haloboronic acid building block.
Roger Adams Laboratory, Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
Eric P
EP
Gillis
Martin D
MD
Burke
D001897:Boronic Acids / Q000138:chemical synthesis* / Q000737:chemistry*; D007098:Imino Acids / Q000737:chemistry*; D015394:Molecular Structure; D013237:Stereoisomerism
D001897:Boronic Acids; D007098:Imino Acids; C533766:N-methyliminodiacetic acid