The Photolytic Disproportionation of Dialkyl 2,2-Di(Phenylseleno)propanedioates
摘要:
Dialkyl-2,2-di(phenylseleno)propanedioates undergo disproportionation to form tetralkyl 1,1,2,2-ethylene tetracarboxylates and diphenyl diselenide upon photolysis. Evidence for the intermediacy of a capto-dative radical intermediate in this process is described.
Radical addition reactions of 2-(phenylseleno)propanedioates to alkenes and alkynes
摘要:
Sunlamp photolysis of methyl or ethyl 2-(phenylseleno)propanedioate with a variety of alkenes and alkynes in benzene yielded addition products in good to excellent yields. The proposed mechanism involves a radical chain process in which addition of a malonate ester radical is followed by phenylseleno transfer. Monosubstituted alkenes,l,l-and l,2-disubstituted alkenes, terminal alkynes, and internal alkynes were shown to undergo this reaction. Addition to diallyl ether led to substituted tetrahydrofurans, characteristic of a process involving initial addition, followed by cyclization prior to phenylseleno transfer. Vinyl arenes, conjugated dienes, and unsaturated carbonyl compounds proved unreactive.
Se–Se Insertion reactions were observed when ethyl diazoacetate and dimethyl diazomalonate were allowed to react with diphenyl diselenide (1) in the presence of catalysts such as copper–bronze or BF3·Et2O.