Chromium photocatalysis: accessing structural complements to Diels–Alder adducts with electron-deficient dienophiles
作者:Susan M. Stevenson、Robert F. Higgins、Matthew P. Shores、Eric M. Ferreira
DOI:10.1039/c6sc03303b
日期:——
alkenes is described. Gathered evidence, via control experiments, isolated intermediates, and measured redox potentials, points to several converging reaction pathways that afford the cyclohexene adducts, including a photochemical [2 + 2] cycloaddition/vinylcyclobutane rearrangement cascade and a substrate excitation/oxidation sequence to a radical cation intermediate. Notably, the accompanying mechanistic
Silenes in organic synthesis: a concise synthesis of (±)-epi-picropodophyllin
作者:Robert D. C. Pullin、Jonathan D. Sellars、Patrick G. Steel
DOI:10.1039/b710370k
日期:——
A concise, seven step synthesis of the aryl tetralin lignan lactone epi-picropodophyllin from piperonal is described. The key steps are a silene diene Diels–Alder reaction and the Hosomi–Sakurai reaction of the resultant silacyclohexene.
The carbocyclic core of massadine has been synthesized relying on a stereoselective formal [3 + 2] cycloaddition of lithiumtrimethylsilyldiazomethane with α,β-unsaturated esters to form a Δ2-pyrazoline moiety followed by facile N–N bond cleavage. A unique feature of the current approach is the direct installation of the tertiary α-amino center and a β-cyano group in a cis arrangement on the resulting