Diastereo- and Enantioselective Synthesis of α,α′-Disubstituted,C 2-Symmetric Ketones Using the SAMP-/RAMP-Hydrazone Method

All articles of this category Starting from simple, symmetric ketones such as, 3-pentanone,1, 3-diphenyl-2-propanone and 2,2-dimethyl-1,3-dioxan-.5-one, α,α′-bisalkylation of the corresponding SAMP-hydrazones ( S )- 2 and ( S )- 8 [( S )-1-(alkylideneamino)-2-(methoxymethyl)pyrrolidines and ( S )-1-(2,2-dimethyl-1,3-dioxan-5-ylideneamino)-2-(methoxymethyl)pyrrolidines, respectively], followed by oxidative cleavage with ozone affords chiral, C 2 -symmetric ketones 5 and ( S,S )- 11 of high diastereo- and enantiomeric purity (de, ee > 98%).