A novel synthesis of the (2R,3S)- and (2S3R)-3-amino-2-hydroxycarboxylic acid derivatives, the key components of a renin inhibitor and bestatin, from methyl (R)- and (S-mandelate
The title synthesis could be accomplished by featuring the [2+2]-cycloaddition reaction of a chiral imine with benzyloxyketene, alcoholysis of the formed 2-azetidinone derivative, and reductive removal of the mandelate-derived benzylic oxygen by way of a 2-oxazolidone derivative.