Diastereoselective Synthesis of trans-2,3,6,7-Tetrahydro-4(5H)-benzofuranones and trans-2,3-Dihydrofurocoumarins via Pyridinium Ylide Assisted Tandem Reactions
作者:Chao-Guo Yan、Ying Han、Hong Hou、Rong Yao、Qin Fu
DOI:10.1055/s-0030-1258279
日期:2010.12
An efficient, one-pot tandem reaction of pyridine, an α-haloacetate, an aromatic aldehyde and cyclohexane-1,3-dione, dimedone or 4-hydrocoumarin in acetonitrile using 1,4-diazabicyclo[2.2.2]octane as a basic catalyst is described. The products, 2,3,6,7-tetrahydro-4(5H)-benzofuranones and 2,3-dihydrofurocoumarins, are obtained in a diastereoselective manner via a mechanism involving in situ formation
吡啶,α-卤代乙酸酯,芳族醛和环己烷-1,3-二酮,二酮或4-氢香豆素在乙腈中以1,4-二氮杂双环[2.2.2]辛烷为碱性进行有效的一锅串联反应描述了催化剂。产物2,3,6,7-四氢-4(5 H)-苯并呋喃酮和2,3-二氢呋喃香豆素是通过非对映选择性方式,通过涉及原位形成吡啶鎓叶立德的机理而获得的。1 H NMR光谱和单晶X射线分析表明产物仅作为反式异构体形成。 串联反应-吡啶鎓叶立德-苯并呋喃酮-呋喃香豆素-非对映选择性