The asymmetricallylicsubstitution of allylphosphates with aryl‐ and alkenylboronates catalyzed by a copper/N‐heterocyclic carbene complex was developed and the γ‐substitution products were obtained with high enantioselectivity (see scheme). To account for the observed influence of the reaction parameters a possible catalytic cycle for this process was proposed.
A potassium‐bis(trimethylsilyl)amide‐mediated cyclopropanation of allylphosphates with silylboronates has been developed. Unlike the reported copper‐catalyzed allylic substitution reactions, the nucleophile selectively attacks at the β‐position of the allylic substrates under the present reaction conditions. The mechanism of this process has also been investigated, thus indicating the involvement
A new type of nucleophile, a 3‐imino nitrile carbanion generated in situ by Thorpe reaction of acetonitrile with a base, was developed successfully and applied in a Pd‐catalyzed asymmetric allylic alkylation with mono‐substituted allyl reagents under Pd/SIOCPhox catalysis, affording β‐enaminonitrile products in high yields with excellent regio‐ and enantioselectivities.
The utility of hydroxylamines as nitrogen nucleophiles was investigated in the iridium-catalyzed regio- and enantioselective allylic substitution. Allylic substitution with hydroxylamines proceeded with good enantioselectivities by using the iridium-complex of bis(oxazolinyl)pyridine ligand. The good regio- and enantioselectivities were also achieved in the reaction with alkylamines, p-anisidine, and 4-methoxyphenol.
Phosphinative cyclopropanation of allyl phosphates with lithium phosphides
作者:Ryo Shintani、Ayase Ohzono、Kentaro Shirota
DOI:10.1039/d0cc04854b
日期:——
A new cyclopropanation reaction of allylphosphates with lithium phosphides has been developed to give cyclopropylphosphines through the formation of both a C–P bond and a cyclopropane ring at the same time, and high selectivity toward cyclopropanation over allylic substitution has been realized by conducting the reaction in the presence of HMPA.