Enantioselective Synthesis and Cross-Coupling of Tertiary Propargylic Boronic Esters Using Lithiation–Borylation of Propargylic Carbamates


  • We thank EPSRC for funding, the Swiss National Foundation for a fellowship (L.C.B.), the University of Bristol for a Post-Graduate Scholarship (A.P.P.), the EPSRC-funded Bristol Chemical Synthesis Doctoral Training Centre for a PhD studentship (M.B.), Inochem-Frontier Scientific for their generous donation of boronic acids and esters, Dr. Mairi Haddow for X-ray analysis, and R. Sanguramath for help in making metal–allene complexes.


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Lithiation–borylation of propargylic carbamates leads to tertiary propargylic boronic esters in very high e.r., provided that ethylene glycol boronic esters are used. These versatile intermediates undergo a range of highly stereoselective transformations, including protodeboronation to give tertiary allenes and Suzuki–Miyaura cross-couplings of tertiary boron species leading to tetrasubstituted allenes with high enantiospecificity.