One-step synthesis of dialkynyl-1, 2-diones and their conversion to fused pyrazines bearing enediyne units

R Faust, C Weber, V Fiandanese, G Marchese, A Punzi

Index: Faust, Ruediger; Weber, Christian; Fiandanese, Vito; Marchese, Giuseppe; Punzi, Angela Tetrahedron, 1997 , vol. 53, # 43 p. 14655 - 14670

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Citation Number: 57

Abstract

A convenient procedure for the preparation of symmetrically end-protected dialkynyl-1, 2- diones 3 from lithium acetylides and oxalyl chloride in the presence of CuBr and LiBr is described. The condensation of 3 with various aromatic and heteroaromatic 1, 2-diamines leads to pyrazine-based α-dialkynylated heterocycles. The enediyne substructure of diethynylquinoxaline can be thermally rearranged in a Bergman cyclization reaction.