Basic and reductive sulfone-directed ring-opening reactions of difluorinated oxa[2.2.1]bicycloheptanes.
Phenylsulfenyl chloride reacts with racemic endo Diels-Alder adduct 4 (DEC = CONEt(2)) to afford lactone 8, which can be reduced and protected in a series of high-yielding steps. Key sulfone 10 can be ring opened under strong base conditions to afford vinyl sulfone 11. Attempted desulfonation resulted in the formation of a monofluoroalkene, but a direct desulfonation/eliminative ring opening with strain relief delivered highly functionalized monocyclic species 16. [reaction: see text]
Crowley
Patrick J
PJ
Syngenta, Ltd., Jealott's Hill International Research Centre, Bracknell, Berks RG42 6ET, United Kingdom.
Fawcett
John
J
Kariuki
Benson M
BM
Moralee
Andrew C
AC
Percy
Jonathan M
JM
Salafia
Vittoria
V