Efficient Approach to 1, 2-Diazepines via Formal Diazomethylene Insertion into the C–C bond of Cyclobutenones

K Sugimoto, R Hayashi, H Nemoto, N Toyooka…

Index: Sugimoto, Kenji; Hayashi, Rie; Nemoto, Hideo; Toyooka, Naoki; Matsuya, Yuji Organic Letters, 2012 , vol. 14, # 13 p. 3510 - 3513

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Citation Number: 11

Abstract

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 4π-ring opening of cyclobutene followed by an 8π-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.