Transition-Metal-Free Allylic Borylation of 1

Identificador:  imarina:5133298

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

Autors:  Maza, Ricardo J; Davenport, Elliot; Miralles, Nuria; Carbo, Jorge J; Fernandez, Elena

Resum:
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.