Site-selectivity control in hetero-Diels–Alder reactions of methylidene derivatives of lawsone through modification of the reactive carbonyl group: an experimental and theoretical study
作者:Maria Tsanakopoulou、Erifili Tsovaltzi、Marina A. Tzani、Periklis Selevos、Elizabeth Malamidou-Xenikaki、Evangelos G. Bakalbassis、Luis R. Domingo
DOI:10.1039/c8ob02383b
日期:——
an acetal derivative of lawsone was synthesized, isolated, and used in tandem Knoevenagel/hetero-Diels–Alderreactions catalyzed by S-proline. The intermediate alkylidene-1,3-diones that were formed in situ reacted with electron rich alkenes to predominantly afford pyrano-1,2-naphthoquinone (β-lapachone) derivatives along with the isomeric pyrano-1,4-naphthoquinone (α-lapachone) derivatives in high to