Unsymmetrical 1,1-diborated multisubstituted sp(3)-carbons formed via a metal-free concerted-asynchronous mechanism.
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 multisubstituted sp(3)-carbon and generation of a Bdan stabilized carbanion, easily conducts a selective protodeboronation sequence.
Department Química Física i Inorgànica, University Rovira i Virgili, C/Marcel lí Domingo s/n, Tarragona, Spain. j.carbo@urv.cat.
Ana B
AB
Cuenca
Jessica
J
Cid
Diego
D
García-López
Jorge J
JJ
Carbó
Elena
E
Fernández