Palladium-Catalyzed Enantioselective Diboration of Prochiral Allenes
作者:Nicholas F. Pelz、Angela R. Woodward、Heather E. Burks、Joshua D. Sieber、James P. Morken
DOI:10.1021/ja044167u
日期:2004.12.1
Pd-catalyzed diboration of prochiral allenes occurs exclusively at the internal position and is remarkably accelerated in the presence of Lewis basic ligand structures. On the basis of preliminary observations, a chiral ligand was employed, and the enantiomeric excess of a variety of diboration products was found to be in the range of 86-92% ee. The chiral diboron reaction products should be useful in organic synthesis, and preliminary experiments suggest that they may participate in allylation reactions with a high level of chirality transfer.
Modular Asymmetric Synthesis of 1,2-Diols by Single-Pot Allene Diboration/Hydroboration/Cross-Coupling
作者:Nicholas F. Pelz、James P. Morken
DOI:10.1021/ol0616891
日期:2006.9.1
Chiral allyl vinyl boronates are generated by catalytic enantioselective diboration of prochiral allenes. They may then be reacted, in situ, with a hydroborating reagent to form a novel triboron intermediate. The least hindered and most reactive C-B bond then participates in cross-coupling wherein the coupling is brought about by the same catalyst as that which catalyzed the diboration reaction. The