Asymmetric synthesis of orthogonally protected trans-cyclopropane gamma-amino acids via intramolecular ring closure.
The synthesis of enantiomerically-enriched trans-cyclopropane amino- and hydroxy-acids can be achieved by intramolecular ring closure in moderate to good yields. The optically active cyclopropane precursors are easily prepared in a short sequence from inexpensive, commercially available olefins and tert-butyl acetate. Several leaving groups and bases were compared for the cyclopropanation step, showing that the diphenylphosphinate and tosyl leaving groups give the best results when used in combination with either LDA or NaHMDS.
Fox
David J
DJ
Cambridge University, University Chemical Laboratory, Lensfield Road, Cambridge, UK. djf34@cam.ac.uk
Pedersen
Daniel Sejer
DS
Warren
Stuart
S
D000596:Amino Acids / Q000138:chemical synthesis* / Q000737:chemistry; D003500:Cyclization; D003521:Cyclopropanes / Q000737:chemistry*
D000596:Amino Acids; D003521:Cyclopropanes; C030797:cyclopropane