A practical deca-gram scale ring expansion of (R)-(−)-carvone to (R)-(+)-3-methyl-6-isopropenyl- cyclohept-3-enone-1

• Leandro de C. Alves^a
• André L. Desiderá^a
• Kleber T. de Oliveira^a
• Sean Newton^b
• Steven V. Ley^{* b}
• Timothy J. Brocksom^{* a}

• ^a Departamento de Química, Universidade Federal de São Carlos, P.O. Box 676, São Carlos – SP, Brazil
• ^b Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK

A route to enantiopure (R)-(+)-3-methyl-6-isopropenyl-cyclohept-3-enone-1, an intermediate for terpenoids, has been developed and includes a highly chemo- and regioselective Tiffeneau–Demjanov reaction. Starting from readily available (R)-(−)-carvone, this robust sequence is available on a deca-gram scale and uses flow chemistry for the initial epoxidation reaction. The stereochemistry of the addition of two nucleophiles to the carbonyl group of (R)-(−)-carvone has been determined by X-ray diffraction studies and chemical correlation.

Read the publication that featured this abstract