A New Co2(CO)8-Mediated Tandem [5 + 1]/[2 + 2 + 1]-Cycloaddition Reaction: A One-Pot Synthesis of Tricyclic δ-Lactones from cis-Epoxy Ene-ynes
摘要:
In the presence of Co2(CO)8 and CO, cis-epoxyalkynes bearing a tether olefin undergo a tandem [5 + 1]/[2 + 2 + 1]-cycloaddition to give tricyclic delta-lactones efficiently in a one-pot operation. The reaction mechanism is proposed to involve a cobalt-coordinated cyclic allene species.
A New Co2(CO)8-Mediated Tandem [5 + 1]/[2 + 2 + 1]-Cycloaddition Reaction: A One-Pot Synthesis of Tricyclic δ-Lactones from cis-Epoxy Ene-ynes
摘要:
In the presence of Co2(CO)8 and CO, cis-epoxyalkynes bearing a tether olefin undergo a tandem [5 + 1]/[2 + 2 + 1]-cycloaddition to give tricyclic delta-lactones efficiently in a one-pot operation. The reaction mechanism is proposed to involve a cobalt-coordinated cyclic allene species.
Enantioselective Epoxidation of Conjugated <i>cis</i>-Enynes by Chiral Dioxirane
作者:Christopher P. Burke、Yian Shi
DOI:10.1021/jo070205r
日期:2007.5.1
This paper describes a highly chemo- and enantioselectiveepoxidation of conjugated cis-enynes using readily available glucose-derived ketone 2 as catalyst and Oxone as oxidant to form cis-propargyl epoxides in high ee's. The interaction between the alkyne group of the substrate and the oxazolidinone moiety of the ketone catalyst as well as the interactions between the substituents on enynes and the