Preparation of Protected β-Keto Aldehydes from β-Keto Esters via Selective Reduction of Acyl(alkoxycarbonyl)ketene Dithioacetals
作者:Eun Bok Choi、In Kwon Youn、Chwang Siek Pak
DOI:10.1055/s-1988-27709
日期:——
The acyl(alkoxycarbonyl)ketene dithioacetals 2 prepared from the corresponding ß-keto esters 1 in almost quantitative yield are reduced selectively with magnesium in methanol and subsequently dealkoxycarbonylated to give protected ß-keto aldehydes 4 high yields.
Copper-Mediated C−N Bond Formation via Direct Aminolysis of Dithioacetals
作者:Jing Kang、Fushun Liang、Shao-Guang Sun、Qun Liu、Xi-He Bi
DOI:10.1021/ol060763c
日期:2006.6.1
to the C-N bond formation via direct aminolysis of dithioacetals 2 and 5 with ammonia, primary or secondary amines are developed under mild conditions. Enaminones 3 and 6 were thus obtained in high to excellent yields with high chemoselectivity. This type of aminolysis reaction presents a newsyntheticapplication of the dithioacetalfunctionality. [reaction: see text]
A novel iron-catalyzed aminolysis of beta-carbonyl 1,3-dithianes with various amines including ammonia, primary and secondary amines, as well as hydrazine hydrate has been developed, leading to the synthesis of steleodefined beta-enaminones and 3,4-disubstituted pyrazoles in good to high yields.