Efficient Approach to 1,2-Diazepines via Formal Diazomethylene Insertion into the C–C bond of Cyclobutenones
摘要:
Efficient monocyclic 1,2-diazepine formation via a tandem electrocyclization reaction of cyclobutenones with lithiodiazoacetate is demonstrated. The reaction proceeds through an oxy anion-accelerated 4 pi-ring opening of cyclobutene followed by an 8 pi-ring closure of the resultant oxy anion-substituted diazo-diene under mild conditions to furnish a 1,2-diazepine via formal diazomethylene insertion into the C-C bond of cyclobutenone.
Facile Addition of Dichloroketene to Acetylenes Mediated by Zinc and Ultrasound
作者:M. Sharon、A. Parker、Carmelo J. Rizzo
DOI:10.1080/00397919508011825
日期:1995.9
Abstract The addition of dichloroketene, generated from trichloroacetyl chloride, zinc dust and ultrasound, to terminal and internal acetylenes is reported. This procedure is a more convenient alternative to Zn-Cu couple.
and silylation of dichlorocyclobutenones, which furnish the boron-substituted and silicon-substituted polyfunctionalized cyclobutenones in high yields. The reactions proceed under mild reaction conditions, show broad substrate scope, and display high chemoselectivity. In addition, a series of transformations of the corresponding products has been realized.