1428538-05-9Relevant articles and documents
Backbone-Modified C2-Symmetrical Chiral Bisphosphine TMS-QuinoxP*: Asymmetric Borylation of Racemic Allyl Electrophiles
Imamoto, Tsuneo,Ito, Hajime,Iwamoto, Hiroaki,Ozawa, Yu,Takenouchi, Yuta
, p. 6413 - 6422 (2021/05/31)
A new C2-symmetrical P-chirogenic bisphosphine ligand with silyl substituents on the ligand backbone, (R,R)-5,8-TMS-QuinoxP*, has been developed. This ligand showed higher reactivity and enantioselectivity for the direct enantioconvergent borylation of cy
Highly diastereo- and enantioselective allylboration of aldehydes using α-substituted allyl/crotyl pinacol boronic esters via in situ generated borinic esters
Chen, Jack L.-Y.,Scott, Helen K.,Hesse, Matthew J.,Willis, Christine L.,Aggarwal, Varinder K.
supporting information, p. 5316 - 5319 (2013/05/21)
Readily available, α-substituted allyl/crotyl pinacol boronic esters often give low E/Z selectivity (with Z favored) in reactions with aldehydes. We found that addition of nBuLi to the pinacol boronic ester followed by trapping of the alkoxide with TFAA leads to an intermediate allyl borinic ester which undergoes allylboration with very high E selectivity. The substrate scope includes primary to tertiary alkyl α-substituents, crotyl substrates, and the previously unreported β-methallyl pinacol boronic esters. The latter give very high Z selectivity under standard conditions which is completely reversed to high E selectivity under the new conditions. Monitoring the reaction by 11B NMR confirmed that the reaction proceeds through a borinic ester intermediate.
