A Convenient One-Pot Method for the Construction of Tetrasubstituted Phenols through a Michael Addition−Aldol Cyclization Sequence
作者:Adrián Covarrubias-Zúñiga、Eduardo Ríos-Barrios
DOI:10.1021/jo9704669
日期:1997.8.1
The sodium salt of dimethyl 1,3-acetonedicarboxylate (1) readily reacts with certain alkynals under mild conditions in THF to give a tetrasubstituted aromatic ring with regiocontrol at the meta-position through a Michael addition-aldol cyclization sequence. Thus the reaction of I with propynal, 2-butynal, 2-pentynal, 2-octynal, 4-(benzoyloxy)-2-butynal, and 4-((tetrahydropyranyl)oxy)-2-butynal at 25 degrees C gave the following products: dimethyl 2-hydroxybenzene-1,3-dicarboxylate (11%), dimethyl 2-hydroxy-4-methylbenzene-1,3-dicarboxylate (45%), dimethyl 4-ethyl-2-hydroxybenzene-1,3-dicarboxylate (46%), dimethyl 2-hydroxy-4-pentylbenzene-1,3-dicarboxylate (42%), dimethyl 2-hydroxy-4-((pivaloyloxy)methyl)benzene (88%), dimethyl 2-hydroxy-4-((benzoyloxy)methyl)benzene-1,3-dicarboxylate (74%), and dimethyl 2-hydroxy-4-(((tetrahydropyranyl)oxy)methyl)benzene-1,3-dicarboxylate (70%).