Asymmetric synthesis of cyclopropanes and dihydrofurans based on phosphine oxide chemistry.
The asymmetric synthesis of gamma-azido trans-cyclopropyl ketones is accomplished via a short, simple and efficient sequence. The cyclopropanation step is achieved by an intramolecular nucleophilic ring closure, with a diphenylphosphinate leaving group, to give trans-cyclopropane exclusively. beta-Keto-diphenylphosphine oxides cyclise to form optically active dihydrofurans. All possible diastereoisomers of dihydrofurans can be prepared selectively starting from the same olefin.
Fox
David J
DJ
University Chemical Laboratory, Lensfield Road, Cambridge, UKCB2 1EW. djf34@cam.ac.uk
Parris
Sean
S
Pedersen
Daniel Sejer
DS
Tyzack
Charles R
CR
Warren
Stuart
S