Highly stereoselective aldol reaction based on titanium enolates from (S)-1-benzyloxy-2-methyl-3-pentanone

Alternative titanium-mediated aldol procedure based on several protected Beta-hydroxy ethyl ketones is surveyed. Eventually, enolization of (S)-1-benzyloxy-2-methyl-3-pentamone with (i-PrO)/TiCl(sub 3)/i-Pr(sub 2)NEt provided a very reactive enolate that afforded the corresponding 2,4-syn-4,5-syn aldol adducts in high yields and diasteromeric ratios with a broad range of aldehydes.