A new and efficient chemoenzymatic route to both enantiomers of α′-acetoxy and α′-hydroxy-α-methoxy cyclic enones
摘要:
A chemoenzymatic synthesis of both enantiomers of the pharmacologically interesting alpha'-acetoxy and alpha'-hydroxy-alpha-methoxy cyclic enones starting from alpha-hydroxy cyclic enones is described. Protection of 1,2-diketones, manganese(III) acetate-mediated acetoxylation followed by enzyme-mediated hydrolysis of alpha'-acetoxy enones gives acetoxy enones 3a-d and hydroxy enones 4a-d with high enantiomeric excesses (up to 99%) and good yields. The transesterification of rac-4b in the presence of DMAP afforded (+)-4b and (-)-3b in high enantiomeric excesses (91-94%) and good chemical yields. (c) 2006 Elsevier Ltd All rights reserved.
Potassium permanganate/carboxylic acid/organic solvent: a powerful reagent for enone oxidation and aryl coupling reactions
作者:Ayhan S. Demir、Hamide Findik
DOI:10.1016/j.tet.2008.05.004
日期:2008.6
with potassiumpermanganate and acetic acid, in which acetoxylation products were obtained in 74–96% yields. The same reaction was carried out with carboxylic acids other than acetic acid, which furnished corresponding acyloxy ketones with the same regioselectivity. For the first time, formyloxylation products were synthesized in a 61–85% yield by using formic acid. The potassiumpermanganate and acetic