Asymmetric Petasis Reactions Catalyzed by Chiral Biphenols
作者:Sha Lou、Scott E. Schaus
DOI:10.1021/ja8018934
日期:2008.6.1
Chiralbiphenolscatalyze the enantioselective Petasis reaction of alkenyl boronates, secondary amines, and ethyl glyoxylate. The reaction requires the use of 15 mol % of (S)-VAPOL as the catalyst, alkenyl boronates as nucleophiles, ethyl glyoxylate as the aldehyde component, and 3 A molecular sieves as an additive. The chiral alpha-amino ester products are obtained in good yields (71-92%) and high
Stereospecific Synthesis of Vinyl(phenyl)iodonium Tetrafluoroborates via Boron-Iodane Exchange of Vinylboronic Acids and Esters with Hypervalent Phenyliodanes
Reaction of vinylboronic acids and esters with hypervalent phenyliodanes in the presence of BF3-Et2O undergoes boron-iodane exchange at O degrees C in dichloromethane yielding vinyl(phenyl)iodonium tetrafluoroborates stereoselectively with retention of configuration. (C) 1997 Elsevier Science Ltd.
Copper-Catalyzed Asymmetric Reduction of β,β-Disubstituted Alkenylboramides
作者:Yeji Park、Jaesook Yun
DOI:10.1021/acs.orglett.9b03400
日期:2019.11.1
A highly enantioselective copper-catalyzed reduction of β,β-disubstituted alkenylboron compounds was developed using hydrosilane. The copperhydride catalyst coordinated with chiral Josiphos ligand efficiently discriminated β-geminal substituents to generate corresponding β-chiral alkylboramides with excellent enantioselectivities up to 99% ee. The enantioselective reduction protocol provides a facile
introduction of diene groups at the omega-side chain have been synthesized and evaluated for their binding affinity for EP(2) and EP(4) receptors. An optimized analog (compound 9b) showed high potency and selectivity for the EP(4) receptor over other known receptors.