A concise synthesis of (S)-N-ethoxycarbonyl-alpha-methylvaline.
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.
Kuethe
Jeffrey T
JT
Department of Process Research, Merck & Co. Inc., Rahway, NJ 07065, USA. jeffrey_kuethe@merck.com
Gauthier
Donald R
DR
Beutner
Gregory L
GL
Yasuda
Nobuyoshi
N
D014633:Valine / Q000031:analogs & derivatives* / Q000138:chemical synthesis
C469556:N-methylvaline; D014633:Valine