Catalytic Diastereoselective Hetero-Diels–Alder Reaction of α-Haloacroleins with Alkenes: Construction of 3,4-Dihydropyran

• DOI: 10.1021/acs.orglett.2c00341
• Publication Date: 2022-03-10T16:34:36Z
• Authors: Lei Zeng; Qian Lei; Weidong Rao; Lizhu Gao
• Keywords: Dihydropyran; Diels–Alder reaction; Conformational isomerism

In this Letter, a catalytic diastereoselective hetero-Diels-Alder reaction of α-haloacroleins with less polarized alkenes was developed, and the resulting 3,4-dihydropyrans were produced in high yields broad substate scope. Mechanism studies showed that 3,4-dihydropyran from ring expansion cyclobutane, which generated contraction initially formed unstable conformer.