A Practical Variant of the Claisen-Eschenmoser Rearrangement: Synthesis of Unsaturated Morpholine Amides
作者:Stefan N. Gradl、Joshua J. Kennedy-Smith、James Kim、Dirk Trauner
DOI:10.1055/s-2002-20453
日期:——
A Claisen-Eschenmoser type rearrangement giving rise to unsaturated morpholine-, piperidine- and pyrrolidine amides is described.
描述了产生不饱和吗啉、哌啶和吡咯烷酰胺的 Claisen-Eschenmoser 型重排。
Reactifs de grignard vinyliques γ fonctionnels
作者:J.G. Duboudin、B. Jousseaume、A Saux
DOI:10.1016/s0022-328x(00)91989-2
日期:1979.3
Primary α-acetylenic alcohols undergo regio- and stereo-specific additiions of Grignard reagents in the presence of cuprous halides. These reactions yield γ-functionally substituted vinylmagnesium compounds. With secondary and tertiary alcohols, the course of the reaction depends on the nature of alcohol and Grignard reagent.
Construction of Complex Cyclobutane Building Blocks by Photosensitized [2 + 2] Cycloaddition of Vinyl Boronate Esters
作者:Spencer O. Scholz、Jesse B. Kidd、Luca Capaldo、Niecia E. Flikweert、Rowan M. Littlefield、Tehshik P. Yoon
DOI:10.1021/acs.orglett.1c00938
日期:2021.5.7
diversification are thus highly desirable. We report herein a photosensitized [2 + 2] cycloaddition with vinyl boronate esters affording straightforward access to complex, densely functionalized cyclobutane scaffolds. Mechanistic studies suggest an activation mode involving energy transfer to the styrenyl alkene rather than the vinyl boronate ester.
Phenyl acetates were selectively obtained in good yields by cyclocarbonylation of 2,4-pentadienyl acetates in the presence of NEt3, Ac2O, and a catalytic amount of palladium complexes such as PdCl2(PPh3)2 at 120-140-degrees-C under 50 atm of CO. No five-membered ring products were observed. A platinum complex PtCl2(PPh3)2 was also effective as a catalyst. The reaction of 5-phenyl-2,4-pentadienyl bromide with M(CO)(PPh3)3 (M = Pd or Pt) under CO gave the corresponding 6-phenyl-3, 5-hexadienoyl complexes in a high yield, which in turn afforded 2-acetoxybiphenyl in 41-51% yield on heating to 160-degrees-C under 50 atm of CO in the presence of NEt3 and Ac2O. Similar 3,5-hexadienoyl complexes are proposed to be intermediates in the catalytic cyclocarbonylation of 2,4-pentadienyl acetates. On the other hand, PdCl2(PPh3)2-catalyzed carbonylation of o-(bromomethyl)(1-alkenyl)-benzenes in the presence of NEt3 and Ac2O gave 2-naphthyl acetates in moderate yields, while the reaction in the absence of Ac2O gave five-membered ring products such as 2-indanones or a tricyclic lactone by incorporation of one or two CO molecules, respectively.
Narjes, Frank; Schaumann, Ernst, Liebigs Annalen der Chemie, 1993, # 8, p. 841 - 846