Anti-selective aldol reactions with titanium enolates of N-glycolyloxazolidinethiones.
[reaction: see text] A highly diastereoselective anti aldol addition utilizing a variety of N-glycolyloxazolidinethiones has been developed. Enolization of an N-glycolyloxazolidinethione with titanium (IV) chloride and (-)-sparteine followed by addition of an aldehyde activated with additional TiCl(4) resulted in highly anti-selective aldol additions, typically with no observable syn isomers. Allyl-protected glycolates demonstrated the highest levels of selection and yields, although O-benzyl and O-methyl glycolyloxazolidinethiones also performed well.
Crimmins
Michael T
MT
Venable and Kenan Laboratories of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA. crimmins@email.unc.edu
McDougall
Patrick J
PJ
D000438:Alcohols / Q000737:chemistry; D006016:Glycolates / Q000737:chemistry; D013237:Stereoisomerism; D013871:Thiones / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*
D000438:Alcohols; D006016:Glycolates; D013871:Thiones; C025096:titanium tetrachloride; D014025:Titanium