Highly stereoselective aldol reaction based on titanium enolates from (S)-1-benzyloxy-2-methyl-3-pentanone.
Alternative titanium-mediated aldol procedures based on several protected beta-hydroxy ethyl ketones have been surveyed. Eventually, enolization of (S)-1-benzyloxy-2-methyl-3-pentanone (1) with (i-PrO)TiCl3/i-Pr2NEt provided a very reactive enolate that afforded the corresponding 2,4-syn-4,5-syn aldol adducts in high yields and diastereomeric ratios with a broad range of aldehydes.
Solsona
Joan G
JG
Departament de Química Orgànica, Universitat de Barcelona, Martí i Franqués 1-11, 08028 Barcelona, Catalonia, Spain.
Nebot
Joaquim
J
Romea
Pedro
P
Urpí
Fèlix
F