Concise and highly selective asymmetric synthesis of acosamine from sorbic acid

A concise and highly selective asymmetric synthesis of methyl N, O-diacetyl-α- l-acosaminide in 7 steps and 15% overall yield from sorbic acid is described. Diastereoselective conjugate addition of lithium ( R)- N-benzyl- N-(α-methylbenzyl)amide to tert-butyl sorbate and subsequent chemo- and diastereoselective ammonium-directed olefinic oxidation of the resultant conjugate addition product { tert-butyl (3 S,α R)-3-[ N-benzyl- N-(α-methylbenzyl)amino]hex-4-ene} have been used as the key steps in a concise and highly selective asymmetric synthesis of the 2,3,6-trideoxy-3-aminohexose l-acosamine. This sequence of two chemical operations allows rapid assembly of the molecular architecture and facilitates the de novo asymmetric synthesis of methyl N, O-diacetyl-α- l-acosaminide in only 7 steps from commercially available sorbic acid in 15% overall yield.