Chemistry of Group 13 element-transition metal linkage - the platinum- andpalladium-catalyzed reactions of (alkoxo)diborons

The metal-catalyzed borylation of alkenes, alkynes, and organic electrophil es with B-B compounds was developed for the synthesis of organoboronic este rs from simple organic substrates. The platinum(0)-catalyzed addition of bi s(pinacolato)diboron to alkenes and alkynes stereoselectively yielded cis-b is(boryl)alkanes or cis-bis(boryl)alkenes. The addition of diboron to 1,3-d ienes with a platinum(0) complex afforded a new access to the cis-1,4-bis(b oryl)butene derivatives which are a versatile reagent for diastereoselectiv e allylboration of carbonyl compounds. The cross-coupling reaction of dibor ons with aryl and vinyl halides or triflates, and allyl chlorides or acetat es was found to yield aryl-, vinyl-, and allylboronates in high yields in t he presence of a base and a palladium catalyst, which provides the first on e-step procedure for the synthesis of organoboronic esters from organic ele ctrophiles. The mechanisms and the synthetic applications of these reaction s are discussed. (C) 2000 Elsevier Science S.A. All rights reserved.