Cycloadditionen. 24. Synthese und Reaktionen vonsec. N-Aryl-buta-2,3-dien-amiden
摘要:
The reaction of aryl isocyanates (1) with allenyl magnesium bromide(2) furnishes the sec. N-aryl-3-butynamides (4), which tend to tautomerize to the 2,3-butadienamides (5). Further heating of 5a-f (bearing benzoid nuclei) leads to decompositon, only 5g (bearing the naphthyl group) undergoes the expected intramolecular Diels-Alder (IMDA) reaction, leading to the benzo-tricycle (7g). By reaction of a second molecule isocyanate 1 the carbamoylation of the NH moiety of 5a, c and of 3g and 4g, resp. takes place. The thereby formed N-aryl-N-butadienoyl ureas (9) either cyclize to furnish the the N-carbamoyl-2-quinolones (10) or undergo the IMDA-reaction leading to the tricyclic compounds (11). The N-butadienoyl-N-(1-naphthyl)ureas (12) only furnish the IMDA-benzo-tricycles (13).
copper‐catalyzed cross‐coupling of 1,2‐dihaloalkenes and amides leads to cyclic β‐haloenamides, which can participate in a second cross‐coupling reaction to efficiently synthesize highly functionalized cyclic enamides. The selectivity of the intramolecular coupling between exo‐ and endocyclic regioisomers is a crucial synthetic factor and can be influenced by the structure of the substrate and the reaction conditions
Hydrosulfonylation of Alkenes with Sulfonyl Chlorides under Visible Light Activation
作者:Sandrine M. Hell、Claudio F. Meyer、Antonio Misale、Jeroen B. I. Sap、Kirsten E. Christensen、Michael C. Willis、Andrés A. Trabanco、Véronique Gouverneur
DOI:10.1002/anie.202004070
日期:2020.7.6
Sulfonyl chlorides are inexpensive reactants extensively explored for functionalization, but never considered for radical hydrosulfonylation of alkenes. Herein, we report that tris(trimethylsilyl)silane is an ideal hydrogen atom donor enabling highly effective photoredox‐catalyzed hydrosulfonylation of electron‐deficient alkenes with sulfonyl chlorides. To increase the generality of this transformation