Synthesis of Vitamin K and Related Naphthoquinones via Demethoxycarbonylative Annulations and a Retro-Wittig Rearrangement
作者:Dipakranjan Mal、Ketaki Ghosh、Supriti Jana
DOI:10.1021/acs.orglett.5b02920
日期:2015.12.4
Anionic annulations of 3-nucleofugal phthalides with α-alkyl(aryl)acrylates involving a demethoxycarbonylation provide a succinct synthesis of vitamin K and related naphthoquinones. Also reported is a new cascade reaction stemming from a Cope–retro-Wittig rearrangement. This cascade leads to direct formation of 1-hydroxy-4-prenyloxynaphthalene-2-carboxylates from the corresponding α-prenyl acrylate
Efficient and general conditions for the formation of stereodefined trisubstituted alkenes by using the rhodium‐catalyzed reaction of unactivated Baylis–Hillman adducts with either organoboronic acids or potassiumtrifluoro(organo)borates are reported (see scheme).