A novel and convenient Pd-catalyzed radical cascade iododifluoromethylation/cyclization of 1,6-enynes with ethyl difluoroiodoacetate is demonstrated. The proposed transformation presents high stereoselectivity under mild and facile reaction conditions, thereby allowing an efficient access to a variety of iodine-containing difluoromethylated pyrrolidines. A possible radical pathway for the transformation
method for the synthesis of trifluoromethyl CF3-substituted spirocyclic compounds containing with a unique quaternarycarboncenter from readily available starting materials has been developed. The reaction provides a facile access to 2H-azirines via cascade cyclization. These compounds constitute a new class of functionalized synthetic intermediates, which can be used for the synthesis of various nitrogen-containing
Copper-Catalyzed [2 + 2 + 3] Annulation of 1,6-Enynes with α-Bromo-1,3-Dicarbonyl Compounds: Synthesis of Dihydrooxepines
作者:Lan Zheng、Yong-Min Liang
DOI:10.1021/acs.joc.7b00879
日期:2017.7.7
Copper-catalyzed [2 + 2 + 3] annulation of 1,6-enynes with α-bromo-1,3-dicarbonyl compounds is described. This reaction provides facile access to seven-membered dihydrooxepines for epidithiodiketopiperazines with two newly formed C–C bonds and one C–O bond.
An iodine-promoted one-pot radical cyclization reaction of 1,6-enynes with sulfonyl hydrazides to provide five-membered and hexatomic ring sulfonylated products under the same conditions is established. This reaction proceeded smoothly in water and gave the corresponding products by using I-2/TBHP instead of expensive and toxic catalysts with C-S and C-I bond formed in one step. This method also allowed easy access to significant functional sulfones for potential applications in medicinal and organic chemistry.