Asymmetric synthesis of trans-disubstituted cyclopropanes using phosphine oxides and phosphine boranes.
The stereocontrolled synthesis of trans-disubstituted cyclopropylketones has been achieved from beta-alkyl, gamma-benzoyl phosphine oxides via a three-step cascade reaction incorporating an acyl transfer, phosphinoyl transfer and cyclisation to form the cyclopropane. Using Evans' chiral oxazolidinone auxiliary and by masking the phosphine oxide moiety as a phosphine borane we have extended the method to the synthesis of enantiomerically-enriched trans-disubstituted cyclopropyl ketones.
Clarke
Celia
C
Cambridge University, University Chemical Laboratory, Lensfield Road, Cambridge, UK CB2 1EW.
Foussat
Stéphanie
S
Fox
David J
DJ
Pedersen
Daniel Sejer
DS
Warren
Stuart
S
D001880:Boranes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003521:Cyclopropanes / Q000138:chemical synthesis* / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D010087:Oxides / Q000737:chemistry*; D010720:Phosphines / Q000737:chemistry*; D013237:Stereoisomerism
D001880:Boranes; D003521:Cyclopropanes; D010087:Oxides; D010720:Phosphines