Olefin Hydroborations with Diamidocarbene–BH3 Adducts at Room Temperature

Dominika Lastovickova,Christopher Bielawski

doi:10.3390/catal6090141

Abstract

An isolable N,N’-diamidocarbene (DAC) was previously shown to promote the B–H bond activation of various BH3 complexes. The resultant DAC–BH3 adducts facilitated olefin hydroborations under mild conditions and in the absence of exogenous initiators. The substrate scope for such transformations was further explored and is described herein. While organoboranes were obtained in quantitative yields from various terminal and internal olefins, use of the latter substrates resulted in intramolecular ring-expansion of the newly formed DAC–borane adducts.

Highlights

InIntrtroodduucctitoionn TThhee hhyyddrroobboorraattiioonn ooff uunnssaattuurraatteedd ccoommppoouunnddss ffoolllloowweedd bbyy ooxxiiddaattiioonn iiss aa ccoommmmoonn aanndd vveerrssaattiillee mmeetthhoodd ffoorr tthhee pprreeppaarraattiioonn ooff aa bbrrooaadd rraannggee ooff aallccoohhoollss [[11,,22]]
The ability of 1a to facilitate the hydroboration of internal olefins was explored
Hydroboration of internal acyclic olefins with 1a

Summary

Introduction

InIntrtroodduucctitoionn TThhee hhyyddrroobboorraattiioonn ooff uunnssaattuurraatteedd ccoommppoouunnddss ffoolllloowweedd bbyy ooxxiiddaattiioonn iiss aa ccoommmmoonn aanndd vveerrssaattiillee mmeetthhoodd ffoorr tthhee pprreeppaarraattiioonn ooff aa bbrrooaadd rraannggee ooff aallccoohhoollss [[11,,22]].. AAss sshhoowwnn iinn SScchheemmee 22,, wwee pprreevviioouussllyy ddeemmoonnssttrraatteedd tthhaatt tthhee NN,,NN’’-‐ddiiaammiiddooccaarrbbeenneess ((DDAACCss)),, aa uunniiqquuee ccllaassss ooff ssttaabbllee ccaarrbbeenneess [[2288]],, aaffffoorrdd 11 uuppoonn eexxppoossuurree ttoo eeiitthheerr BBHH33––ppyyrriiddiinnee oorr BBHH33––SSMMee22[[2299]].. HHyyddrroobboorraattiioonn ooff ccyycclloohheexxeennee wwiitthh 11aa ffoolllloowweedd bbyy iinnttrraammoolleeccuullaarr rriinngg-‐‐eexxppaannssiioonn..

Results

Conclusion