Carbonylative Ring Opening of Terminal Epoxides at Atmospheric Pressure
作者:Scott E. Denmark、Moballigh Ahmad
DOI:10.1021/jo7014455
日期:2007.12.1
[GRAPHICS]The carbonylative opening of terminal epoxides under mild conditions has been developed using CO2-(CO)(8) as the catalyst. Under I atm of carbon monoxide and at room temperature in methanol, propylene oxide is converted to methyl 3-hydroxybutanoate in up to 89% yield. This transformation is general for many terminal epoxides bearing alkyl, alkenyl, aryl, alkoxy, chloromethyl, phthalimido, and acetal functional groups. The opening takes place without epimerization at the secondary stereocenter.
Enantioselective synthesis induced by chiral epoxides in conjunction with asymmetric autocatalysis
5-Pyrimidyl alkanol with an enantiomeric excess of up to 96% was formed using chiral epoxides as a chiral initiator in the enantioselective addition of diisopropylzinc to pyrimidine-5-carbaldehyde, in conjunction with asymmetric autocatalysis. (C) 2004 Elsevier Ltd. All rights reserved.
Humicola lanuginosa lipase-catalyzed enantioselective resolution of β-hydroxy sulfides: versatile synthons for enantiopure β-hydroxy sulfoxides
Humicola lanuginosa lipase-catalyzed acylation of beta -hydroxy sulfides provides both the (R)- and (S)-enantiomers in high enantiomeric purity. In two cases the resolved hydroxy sulfides were oxidized to give beta -hydroxy sulfoxides in > 99% e.e. The effect of substituents on enantioselectivity is discussed. (C) 2001 Elsevier Science Ltd. All rights reserved.