Enantio- and Diastereoselective Synthesis of 1,2-Hydroxyboronates through Cu-Catalyzed Additions of Alkylboronates to Aldehydes
作者:Matthew V. Joannou、Brandon S. Moyer、Simon J. Meek
DOI:10.1021/jacs.5b03477
日期:2015.5.20
The first catalytic enantio- and diastereoselective synthesis of 1;2-hydroxyboronates is reported. Reactions are promoted by a readily available chiral monodentate phosphoramidite copper complex in the presence of an alkyl 1,1-diboron reagent. Products contain two contiguous stereogenic centers and are obtained in up to 91% yield, >98:2 d.r., arid 98:2 e.r. The reaction is tolerant of aryl and vinyl aldehydes, and the 1,2-hydroxyboronate products can be transformed into versatile derivatives. Mechanistic experiments indicate control of absolute stereochemistry of the alpha-boryl component.
Fine regioselective tuning in the oxidation of sec,sec 1,2-diols by dimethyldioxirane
作者:Paolo Bovicelli、Anna Sanetti、Paolo Lupattelli
DOI:10.1016/0040-4020(96)00615-1
日期:1996.8
Non symmetric sec,sec 1.2-diols and their O-isopropylidene derivatives undergo a regioselectiveoxidation by dimethyldioxirane depending on the electronic effects of the substituents. These results support previous views about the concerted -insertion mechanism via a polar transition state.