Designing the reactant molecule of an initial reaction,
based on
quantum chemical pathway exploration, enabled us to access a new reaction,
i.e., the tetraborylation reaction of p-benzynes
generated from 1,2-diethynylbenzene derivatives, using bis(pinacolato)diborane(4)
(B2pin2). Based on the reaction path network
generated via the artificial-force-induced reaction (AFIR) method,
desired and undesired paths were identified and used to modify the
chemical structure of the reactant. After the in silico screening,
the optimal structure of the reactant was determined to be a 1,2-diethynylbenzene
derivative with a butylene linker. The reaction of the optimized reactant
and its derivatives with an excess of B2pin2 gave the tetraborylated products in good yields (up to 58%). It
is quite intriguing that the two carbons of p-benzyne
behave formally as dicarbenes in this reaction.