Organocatalyzed Microwave-Assisted Competing Cyclization of Cyanopropargylic Alcohols with Carboxylic Acids: 4-Cyano-3(2H)-furanones versus 4-Cyano-[(Z)-3-cyanomethylene]-2,3-dihydrofurans
作者:Boris Trofimov、Anastasiya Malkina、Anton Stepanov、Lyubov Sobenina、Olesya Shemyakina、Igor Ushakov、Vladimir Smirnov
DOI:10.1055/s-0035-1561591
日期:——
reactant ratio, catalyst content) and the reactant structure, the 2:1 adduct formation being favored by an excess of cyanopropargylic alcohol, lower catalyst content, and bulky substituents at the carboxylic functions. Both competing reactions proceed via the same intermediates, keto esters, which either intramolecularly cyclize to the 1:1 adducts, or intermolecularly add the second molecule of cyanopropargylic
摘要 首次表明,在微波辐射(MeCN,100°C,1.2 atm)下三乙胺(5–100 mol%)存在下,氰基炔丙醇与羧酸的反应遵循两条竞争途径生成4-氰基-3(2 H)-呋喃酮(1:1加合物)和4-氰基-[(Z)-3-氰基亚甲基] -2,3-二氢呋喃(2:1加合物),产率中等至良好。产物的比例取决于反应条件(反应物比例,催化剂含量)和反应物结构,其中2:1加合物的形成受氰基炔丙醇过量,催化剂含量较低和羧基官能团取代的影响。两种竞争反应均通过相同的中间体酮酸酯进行,该中间体在分子内环化为1:1加合物,或在分子间添加氰丙炔醇的第二个分子以生成2:1加合物。 首次表明,在微波辐射(MeCN,100°C,1.2 atm)下三乙胺(5–100 mol%)存在下,氰基炔丙醇与羧酸的反应遵循两条竞争途径生成4-氰基-3(2 H)-呋喃酮(1:1加合物)和4-氰基-[(Z)-3-氰基亚甲基] -2,3-