Photoredox Generated Carbonyl Ylides Enable a Modular Approach to Aryltetralin, Dihydronaphthalene, and Arylnaphthalene Lignans
作者:Edwin Alfonzo、Alexandra M. Millimaci、Aaron B. Beeler
DOI:10.1021/acs.orglett.0c02286
日期:2020.8.21
A one-pot synthesis of dihydronaphthalenes and arylnaphthalenes from epoxides and common dipolarophiles is described. The reaction proceeds through photoredox activation of epoxides to carbonyl ylides, which undergo concerted [3 + 2] dipolar cycloaddition with dipolarophiles to provide tetrahydrofurans or 2,5-dihydrofurans. In the same flask, acid promoted rearrangement affords densely functionalized
The invention relates to a process for the preparation of 1-alkyl-1,2,3,4-tetrahydroisoquinoline derivatives of the general formula ##STR1## The compounds can be used for the preparation of tetrahydroisoquinolines of the reticuline type, or of the norreticuline type, by reductive removal of the OH groups or, if they carry an acyl protective group on the nitrogen, for the preparation of isoquinolines of the papaverine type by acid-catalyzed hydrolysis with removal of the acyl groups and simultaneous removal of the hydroxyl groups. These 1-alkyl-1,2-dihydroisoquinoline derivatives can then be used for the preparation of isoquinolines of the papaverine type by aromatization by means of acids or hydrazine.