Copper-catalyzed 1, 2-double amination of 1-halo-1-alkynes. concise synthesis of protected tetrahydropyrazines and related heterocyclic compounds

Y Fukudome, H Naito, T Hata…

Index: Fukudome, Yasuhiro; Naito, Hiroyuki; Hata, Takeshi; Urabe, Hirokazu Journal of the American Chemical Society, 2008 , vol. 130, # 6 p. 1820 - 1821

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Citation Number: 90

Abstract

Reaction of N, N'-di (p-toluenesulfonyl)-1, 2-diamine, 1-bromo-1-alkyne, K3PO4, and a catalytic amount of CuI in hot DMF afforded N, N'-di (p-toluenesulfonyl)-1, 2, 3, 4- tetrahydropyrazines in good yields. The reaction most likely involves (i) monoalkynylation of the diamine derivative with 1-bromo-1-alkyne, and (ii) 6-endo-dig ring closure between the acetylenic bond and another sulfonylamine moiety of the diamine. When the starting 1, 2- ...