Synthesis of 4-Ynamides and Cyclization by the Vilsmeier Reagent to Dihydrofuran-2(3H)-ones
Zhaocheng Zhang, Rapolu Kiran Kumar, Guangzhi Li, Dongmei Wu* and Xihe Bi*
*College of Pharmacy, Jiamusi University, Jiamusi 154007, China, Email: wudmei67163.com, bixh507nenu.edu.cn
J. Zheng, J.-H. Lin, L.-Y. Yu, Y. Wei, X. Zheng, J.-C. Xiao, Org. Lett., 2015, 17, 6126-6129.
The room-temperature nucleophilic addition of vinyl azides to propargylic alcohols in the presence of a catalytic amount of BF3·Et2O provides 4-ynamides. The procedure is operationally convenient, shows broad substrate scope, and tolerates many functional groups. Further, a Vilsmeier intramolecular cyclization of 4-ynamides gives dihydrofuran-2(3H)-ones with the alkyne group as the nucleophile.
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propargylation, amides, lactones, Vilsmeier reaction