title: A concise synthesis of (S)-N-ethoxycarbonyl-alpha-methylvaline.
abstract: A practical and efficient protocol for the three-step synthesis of (S)-N-ethoxycarbonyl-alpha-methylvaline 3 is described which utilizes readily available commercial starting materials. The key transformations involve resolution-crystallization of tartrate salt 6 followed by a one-pot procedure for the preparation of 3 which is isolated as the dicyclohexylamine salt in 45% overall yield and in 91-95% ee.
authors: Department of Process Research, Merck & Co. Inc., Rahway, NJ 07065, USA. jeffrey_kuethe@merck.com
authors: Jeffrey T
authors: JT
authors: Kuethe
authors: Donald R
authors: DR
authors: Gauthier
authors: Gregory L
authors: GL
authors: Beutner
authors: Nobuyoshi
authors: N
authors: Yasuda
mesh_terms: D014633:Valine / Q000031:analogs & derivatives* / Q000138:chemical synthesis
chemical_list: C469556:N-methylvaline; D014633:Valine