Catalytic Use of Selenium Electrophiles in Cyclizations
摘要:
[GRAPHICS]A new and convenient one-pot method for a catalytic addition-elimination reaction using selenium electrophiles has been developed. In the presence of 5 mol % diphenyl diselenide, [bis(trifluoroacetoxy)iodo]benzene in acetonitrile converted a range of (E)-3-butenoic acids into the corresponding butenolides in good yields.
Borane-Catalyzed Reductive α-Silylation of Conjugated Esters and Amides Leaving Carbonyl Groups Intact
作者:Youngchan Kim、Sukbok Chang
DOI:10.1002/anie.201508669
日期:2016.1.4
valuable α‐silyl carbonyl products. The α‐silylation occurs chemoselectively, thus leaving the labile carbonylgroups intact. The reaction features a broad scope of both acyclic and cyclic substrates, and the synthetic utility of the obtained α‐silyl carbonyl products is also demonstrated. Mechanistic studies revealed two operative steps: fast 1,4‐hydrosilylation of conjugated carbonyls and then slow
本文描述了由B(C 6 F 5)3催化的α,β-不饱和酯和酰胺的氢化硅烷化反应,以提供具有合成价值的α-甲硅烷基羰基产物。α-甲硅烷基化是化学选择性发生的,因此保留了不稳定的羰基。该反应具有无环和环状底物的广泛范围,并且还证明了所得α-甲硅烷基羰基产物的合成效用。机理研究揭示了两个操作步骤:共轭羰基的快速1,4-氢化硅烷化,然后减慢甲硅烷基醚中间体的甲硅烷基迁移。
DIANIONS OF β-HYDROXY SULFONES: NEW AND GENERAL APPROACH TO SELECTIVE SYNTHESIS OF 2(5<i>H</i>)-FURANONES
electrophiles including alkyl halides, carbonyl compounds, and sodium iodoacetate. A convenient synthetic method for 4-alkyl- and 5-alkyl-2(5H)-furanones has been developed by using these dianions. A new synthetic approach to trans-3,4-bis(3-hydroxybenzyl)dihydro-2(3H)-furanone, the first lignan found in humans, via a facile reduction of 2(5H)-furanone with Mg-methanol is also decribed.
Asymmetric Olefin Isomerization of Butenolides via Proton Transfer Catalysis by an Organic Molecule
作者:Yongwei Wu、Ravi P. Singh、Li Deng
DOI:10.1021/ja205674x
日期:2011.8.17
general olefin isomerization was realized via biomimetic protontransfer catalysis with a new chiral organic catalyst. A broad range of mono- and disubstituted β,γ-unsaturated butenolides were transformed into the corresponding chiral α,β-unsaturated butenolides in high enantioselectivity and yield in the presence of as low as 0.5 mol % catalyst. Mechanistic studies have revealed the protonation as the
Asymmetric 1, 4-additions to 5-alkoxy-2 (5H)-furanonesenantioselective synthesis and absolute configuration determination of β-amino-δ-butyrolactones and amino diols
作者:B. de Lange、F. van Bolhuis、Ben L. Feringa
DOI:10.1016/s0040-4020(01)89149-3
日期:1989.1
es via asymmetric conjugate addition of various amines to 5-menthyloxy-2(5H)-furanone is described. This route provides access to new multifunctionalhomochiral building blocks. The absolute configuration of the β-amino-δ-butyrolactones is established by X-ray analysis and 1H NMR correlation. Theconjugate addition of amines to 2[5H]-furanone, 5-alkyl-2[5H]-furanones and 5-alkoxy-2[5H]-furanones was
描述了通过将各种胺不对称共轭加成到5-薄荷基氧基-2(5H)-呋喃酮中来合成对映体纯的β-氨基-δ-丁内酯。这条路线提供了通往新的多功能同构构件的途径。通过X射线分析和1 H NMR相关性确定了β-氨基-δ-丁内酯的绝对构型。研究了将胺共轭添加到2 [5H]-呋喃酮,5-烷基-2 [5H]-呋喃酮和5-烷氧基-2 [5H]-呋喃酮中,并观察到由于2 [5H]-呋喃酮具有增强的反应性,这是由于γ-烷氧基效应。不对称胺加成的合成效用以有效途径说明了各种光学纯的2-氨基-1,4-丁二醇的合成。
A new synthesis of α,β-unsaturated γ- and δ-lactones via intramolecular acylation of α-sulfinyl carbanion
作者:Manat Pohmakotr、Prapanpong Jarupan
DOI:10.1016/s0040-4039(00)98975-5
日期:1985.1
A newsynthesis of α,β-unsaturated γ- and δ-lactones involving the intramolecular acylation of α-sulfinyl carbanion followed by pyrolysis is described.