1‐disubstituted alkenes via radicaladdition‐anionic cyclization cascade has been successfully developed. Another new protocol based on photocatalytic allylation and cyclopropanation cascade was also described between allylic halide and halomethyl radical. In addition to the successful use of bis‐catecholato silicates as the alkylradical precursors, the acyl and alkylradicals derived from 1,4‐dihydropyridines
A hydroxy group chelation‐assisted stereospecific oxidative cross‐coupling reaction between alkenes was developed under mild reaction conditions. In the presence of palladium catalyst, the alkenes tethered with hydroxy functionality can couple efficiently with electron‐deficient alkenes to form the corresponding multi‐substituted olefin products. The hydroxy group on the substrate could play dual roles
Metal cation-exchanged montmorillonite (M
n+
-mont)
works in acetonitrile at 80 °C as a Lewis acid catalyst for
the intermolecular carbonyl-ene reaction of
α-methylstyrenes with paraformaldehyde to give the
corresponding homoallylic alcohols, Zr
4+
-mont being the most
effective of the many M
n+
-mont catalysts examined.
Similarly, the catalyst is also useful for the highly stereoselective
intramolecular cyclization of citronellals to afford isopulegols, the
reaction being much faster. Regeneration of the catalyst is confirmed
for Zr
4+
-mont, which can be effectively recycled at least
five times.
Enantioselective Copper‐Catalyzed Borylative Cyclization for the Synthesis of Quinazolinones
作者:Quentin Dherbassy、Srimanta Manna、Chunling Shi、Watcharapon Prasitwatcharakorn、Giacomo E. M. Crisenza、Gregory J. P. Perry、David J. Procter
DOI:10.1002/anie.202103259
日期:2021.6.21
Quinazolinones are common substructures in molecules of medicinal importance. We report an enantioselectivecopper-catalyzed borylative cyclization for the assembly of privileged pyrroloquinazolinone motifs. The reaction proceeds with high enantio- and diastereocontrol, and can deliver products containing quaternary stereocenters. The utility of the products is demonstrated through further manipulations
Palladium-Catalyzed Enantioselective Redox-Relay Heck Arylation of 1,1-Disubstituted Homoallylic Alcohols
作者:Zhi-Min Chen、Margaret J. Hilton、Matthew S. Sigman
DOI:10.1021/jacs.6b06994
日期:2016.9.14
An enantioselective redox-relay oxidative Heck arylation of 1,1-disubstituted alkenes to construct β-stereocenters was developed using a new pyridyl-oxazoline ligand. Various 1,2-diaryl carbonyl compounds were readily obtained in moderate yield and good to excellent enantioselectivity. Additionally, analysis of the reaction outcomes using multidimensional correlations revealed that enantioselectivity