Photochemical [2 + 2] cycloaddition of acetylene to chiral 2(5H)-furanones.
The [2 + 2] photocycloaddition of acetylene to chiral 2(5H)-furanones was investigated. The influence on the chemical yield and facial diastereoselectivity of the substituent at the stereogenic center and also the effect of a 4-methyl group were evaluated. A mechanistic proposal based on a simple theoretical conformational analysis is presented. Using a C(2)-symmetric bis(lactone) as the substrate, a diastereomeric excess higher than 98% was found.
Alibés
Ramon
R
Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
de March
Pedro
P
Figueredo
Marta
M
Font
Josep
J
Fu
Xiaolin
X
Racamonde
Marta
M
Alvarez-Larena
Angel
A
Piniella
Juan F
JF