Sulfur-controlled and rhodium-catalyzed formal (3 + 3) transannulation of thioacyl carbenes with alk-2-enals and mechanistic insights
作者:Qiuyue Wu、Ziyang Dong、Jiaxi Xu、Zhanhui Yang
DOI:10.1039/d1ob00116g
日期:——
A rhodium-catalyzed denitrogenative formal (3 + 3) transannulation of 1,2,3-thiadiazoles with alk-2-enals is achieved and a mechanistic investigation is performed, with an inverse KIE of 0.49 obtained.
Two-Carbon Homologation of Aldehydes and Ketones to α,β-Unsaturated Aldehydes
作者:Richard J. Petroski、Karl Vermillion、Allard A. Cossé
DOI:10.3390/molecules16065062
日期:——
Phosphonate reagents were developed for the two-carbonhomologation of aldehydes or ketones to unbranched- or methyl-branched α,β-unsaturatedaldehydes. The phosphonate reagents, diethyl methylformyl-2-phosphonate dimethylhydrazone and diethyl ethylformyl-2-phosphonate dimethylhydrazone, contained a protected aldehyde group instead of the usual ester group. A homologation cycle entailed condensation of the
膦酸酯试剂被开发用于醛或酮的双碳同系化为未支化或甲基支化的 α,β-不饱和醛。膦酸酯试剂,二乙基甲基甲酰基-2-膦酸酯二甲基腙和二乙基乙基甲酰基-2-膦酸酯二甲基腙,含有受保护的醛基而不是通常的酯基。同系化循环需要将试剂与起始醛缩合,然后用 1 M HCl 和石油醚的双相混合物去除二甲基腙保护基团。这种稳健的两步法适用于各种醛和酮。在缩合和脱保护步骤后,不饱和醛产物的总分离产率为 71% 至 86%。
Reaction of α,β-unsaturated aldehydes with hydrogen peroxide catalysed by benzeneseleninic acids and their precursors
作者:Ludwik Syper
DOI:10.1016/s0040-4020(01)86890-3
日期:1987.1
Oxidation of α,β-unsaturated aldehydes with hydrogenperoxide catalysed by benzeneseleninic acids and their precursors has been investigated. Bis 2-nitrophenyl diselenide has proved to be the most effective catalyst. The major products resulting from the oxidation are vinyl formates (a) which on hydrolysis give saturated aldehydes or ketones (g) having the carbon chain shortened by one carbon atom
A Regioselective Cyclohexannulation Procedure<i>via</i>Dienamine [4 + 2] Cycloaddition. Synthesis of Functionalised Decalins
作者:Roger L. Snowden、Simon M. Linder、Manfred Wüst
DOI:10.1002/hlca.19890720505
日期:1989.8.9
A regioselective cyclohexannulation procedure, whose key step involves the [4 + 2] cycloaddition of dienamines 12–24 with methyl acrylate, allows the conversion of cycloalkanones 1–11 to bicyclic dienoates 25 – 37. The chemistry of 26 is briefly examined and, in the context of organoleptic studies concerning functionalised 5,5,9-tri-methyldecalins, the transformation of 37 to ketones 44 and 46 as well
The first copper-catalyzed imidovinylation of alkynes has been developed, which grants facile access to various (E)-2-imido-2,4-dienals with high stereoselectivity under mild conditions. This transformation also represents the first 1,3-carbon migration of propargylic alcohols and their derivatives.