Unsymmetrical 1,1-diborated multisubstituted sp3-carbons formed via a metal-free concerted-asynchronous mechanism

Identifier:  imarina:3665101

Handle: https://hdl.handle.net/20.500.11797/imarina3665101

Authors:  Cuenca, AB; Cid, J; García-López, D; Carbó, JJ; Fernández, E

Abstract:
We have experimentally proved the unsymmetrical 1,1-diboration of diazo compounds, formed in situ from aldehydes and cyclic and non-cyclic ketones, in the absence of any transition metal complex. The heterolytic cleavage of the mixed diboron reagent, Bpin-Bdan, and the formation of two geminal C-Bpin and C-Bdan bonds has been rationalised based on DFT calculations to occur via a concerted-asynchronous mechanism. Diastereoselection is attained on substituted cyclohexanones and DFT studies provide understanding on the origin of the selectivity. The alkoxide-assisted selective deborylation of Bpin from the multisubstituted sp3-carbon and generation of a Bdan stabilized carbanion, easily conducts a selective protodeboronation sequence