2-Alkoxy-2-amino-Δ<sup>3</sup>-1,3,4-oxadiazolines as Novel Sources of Alkoxyaminocarbenes
作者:Philippe Couture、Johan K. Terlouw、John Warkentin
DOI:10.1021/ja953813+
日期:1996.1.1
Nucleophilic Carbenes in Organic Synthesis. Construction of Functionalized Hydroindolones <i>via</i> a Novel Reaction Pathway of Dimethoxycarbene
作者:James H. Rigby、Alexandre Cavezza、Gulzar Ahmed
DOI:10.1021/ja962784f
日期:1996.1.1
Spiro-fused 2-alkoxy-2-amino-Δ<sup>3</sup>-1,3,4-oxadiazolines. Synthesis and thermolysis to corresponding aminooxycarbenes
作者:Philippe Couture、John Warkentin
DOI:10.1139/v97-153
日期:1997.9.1
undergo thermolysis in benzene at 90 °C with first-order rate constants of (1.6–50) × 10−5 s−1. The dependence of these rate constants on the nature of the substituents present on the oxadiazoline ring is consistent with a mechanism involving a carbonylylideintermediate. Substituents on N of the oxazolidine or tetrahydro-1,3-oxazine moieties play a major role in determining the fragmentation pathways
hydantoins. Major products from the reactions of the N-carbonyl carbenes with dimethyl acetylenedicarboxylate or with methyl propiolate were 2-oxazolines resulting from apparent acyl transfers from N to C in the proposed dipolar intermediates; minor products of 1:2 (carbene:trap) stoichiometry were also observed. Keywords: nucleophilic carbene, aminooxycarbene, oxadiazoline, amide rotation, oxazolidine
Δ3-1,3,4-恶二唑啉在苯中在 90°C 下热解产生的一系列恶唑烷-2-亚基和一个四氢-1,3-恶嗪-2-亚基通过插入 OH 键被截获酚类。在两种情况下,初始产物重排为 N-(2-芳氧基乙基)-N-甲基甲酰胺。围绕这些最终产物的酰胺 CN 键旋转的活化能测量为 20.4 kcal/mol。氨基氧卡宾与两当量的异氰酸甲酯或苯基酯反应生成螺合乙内酰脲。N-羰基卡宾与乙炔二甲酸二甲酯或丙炔酸甲酯反应的主要产物是 2-恶唑啉,这是由拟议的偶极中间体中从 N 到 C 的明显酰基转移产生的;还观察到 1:2(卡宾:陷阱)化学计量的次要产物。关键词:亲核卡宾,