Enantioselective Rhodium-Catalyzed Conjugate Alkynylation of 5-Benzylidene Meldrum’s Acids with TMS-acetylene
作者:Eric Fillion、Alexander K. Zorzitto
DOI:10.1021/ja905336p
日期:2009.10.21
The enantiosetective alkynylation of benzylidene Meldrum's acids has been successfully achieved through rhodium-catalyzed addition of TMS-acetylene in the presence of bisphosphine ligand 3,5-Xylyl-MeOBIPHEP. The resulting Meldrum's acids were obtained in good yields and up to 99% enantiomeric excess. The alkynylation method is carried out under mild reactions conditions and is compatible with an array of functional groups.
Sc(OTf)<sub>3</sub>-Catalyzed Conjugate Allylation of Alkylidene Meldrum’s Acids
作者:Aaron M. Dumas、Eric Fillion
DOI:10.1021/ol9003959
日期:2009.5.7
Alkylidene Meldrum’s acids are allylated in a conjugate fashion by allyltin nucleophiles under mild Sc(OTf)3-catalyzed conditions. The addition is functional group tolerant and reactions with nonracemic alkylidenes are highlydiastereoselective. Allylation of alkylidenes derived from α-ketoesters yield all-carbon quaternary stereocenters.