Cycloadditions of 2-aza-1,3-dienes to aldehydes: a Diels-Alder strategy for the diastereoselective hydroxyalkylation of carboxylic acid derivatives
摘要:
2-Aza-1,3-dienes 1 which are readily prepared from carboxylic acids cycloadd to aldehydes to give good yields of 1,3-oxazinones 3. The cycloadditions were highly diastereoselective in favour of the endo adducts. Hydrolysis of 1,3-oxazinones 3 stereoselectively yielded the corresponding beta-hydroxyamides 4. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.
已经通过三种途径制备了在C-3处带有活化三烷基甲硅烷基氧基的2-Aza-1,3-二烯。第一条途径涉及N-酰基酰亚胺的甲硅烷基化,其可从亚氨基醚盐酸盐和酰氯容易获得。根据朝向这些双活化二烯的更通用的途径,通过在三乙胺的存在下与酰氯反应,将由不可烯化的醛衍生的N-三烷基甲硅烷基酰亚胺酯和N-三烷基甲硅烷基亚胺方便地以一锅法转化为相应的氮杂二烯。最后,可以通过在三乙胺的存在下用三烷基甲硅烷基三氟甲磺酸酯在两个氧上将戊二酰亚胺直接甲硅烷基化来制备环状二烯。2-氮二烯的构型和构象已由1 H,13确定C和15 N NMR光谱。
Diastereoselective β-Hydroxyalkylation
and β-Hydroxycarboxylation of Amides by a Diels-Alder
Strategy
作者:Léon Ghosez、Deogratias Ntirampebura
DOI:10.1055/s-2002-34367
日期:——
Acid chlorides readily condensed with N-silylated imines in the presence of a base to generate 2-azadienes. These underwent Diels-Alder cycloadditions with a wide variety of aldehydes.. In most cases the cycloadditions were diastereoselective in favor of the 3,4-cis-oxazinone adducts. Ethanolysis stereoselectively yielded products of hydroxyalkylation or hydroxycarboxylation of the primary amides derived