A stereoselective synthesis of the pentaketide lactone (3R,4S,5S,9S)-3,5,9-trihydroxy-4-methylundecanoic acid delta-lactone has been achieved. (c) 2006 Published by Elsevier Ltd.
作者:Schroetter, Eberhard、Luong, Tran Thanh、Schick, Hans
DOI:——
日期:——
Metal-Dependent Reaction Tuning with Cyclopentylmetal Reagents: Application to the Asymmetric Synthesis of (+)-α-Conhydrine and (<i>S</i>)-2-Cyclopentyl-2-phenylglycolic Acid
The reaction of halocyclopentane organometallic reagents can be tuned by the choice of metal (see scheme). Cyclopentylmagnesium bromide reduces aldehydes and ketones to the corresponding alcohols. However, in the presence of ZnCl2, normal Grignardaddition to the ketones gives tertiary alcohols with complete diastereoselectivity. These protocols were used in the asymmetric synthesis of two medicinally
A novel stereoselective synthesis of (−)-β-conhydrine from (R)-2,3-O-cyclohexylidine glyceraldehyde
作者:Mallam Venkataiah、Nitin W. Fadnavis
DOI:10.1016/j.tet.2009.06.060
日期:2009.8
stereoselective synthesis of (−)-β-conhydrine is achieved. Stereoselective Grignard reaction of (R)-2,3-O-cyclohexylidine glyceraldehyde with ethylmagnesiumbromide, chelation controlled stereoselective Grignard reaction of allyl imine derivative with allyl magnesiumbromide, and ring-closing metathesis (RCM) of the diallyl product provides (−)-β-conhydrine in high yield.