Cu(II)-Catalyzed [3 + 1 + 1 + 1] Cyclization of 1,3-Diketones and 2-Naphthols Using <i>N</i>,<i>N</i>-Dimethylethanolamine as a Dual Carbon Synthon for the Synthesis of 2<i>H</i>-Chromenes

Abstract

Reactions with diverse C1 synthons to realize homologation were well explored. However, homologations occurring twice with one C1 synthon in a reaction were less reported. We disclose herein a Cu(II)-catalyzed novel and efficient synthesis of 2<i>H</i>-chromenes from 2-naphthols, 1,3-diketones, and <i>N</i>,<i>N</i>-dimethylethanolamine (DMEA) as a dual carbon synthon. Various 2<i>H</i>-chromenes with different functional groups are constructed in moderate to good yields. This is the first report that DMEA acts as a dual C1 synthon.