ISHC2015

A scalable, asymmetric synthesis of (3aS,6aS)-6a-(5-bromo-2-fluorophenyl)-1-((R)-1-phenylpropyl)tetrahydro-1H,3H-furo[3,4-c]isoxazole (1), a key intermediate in the synthesis of LY2886721 is reported.  Highlights of the synthesis include: (1) The development of an asymmetric [3+2] intramolecular cycloaddition through a combined kinetic modeling and experimental approach; (2) The development of a new synthesis of (R)-N-(1-phenylpropyl)hydroxylamine tosylate (2) which proceeds through a p-anisaldehyde imine and avoids the formation of toxic hydrogen cyanide gas as a by-product.  Results of a synthesis executed on the multi-100 kg scale (which proceeded in 36% overall yield) will be discussed.