Transition-Metal-Free Allylic Borylation of 1,3-Dienes

Identifier:  imarina:5133298

Handle: https://hdl.handle.net/20.500.11797/imarina5133298

Authors:  Maza, RJ; Davenport, E; Miralles, N; Carbó, JJ; Fernández, E

Abstract:
This work explains the reactivity of diboron reagents with 1,3-dienes in a transition-metal-free context. The sole addition of Na2CO3 (30 mol %) to bis(pinacolato)diboron in MeOH allows the 1,4-hydroboration of cyclic and noncyclic 1,3-dienes. The electronic influence on the substrate guarantees the conjugated 1,4-hydroboration versus 1,2-diboration. DFT calculations show that the distribution of charge in the allylic anion intermediate governs the selectivity toward 1,4-hydroboration, while the favored trans configuration in diene reagents determines the preference for the E allyl boronate products.