title: Stereoselective addition of the titanium enolate of N-acetyl (4S)-isopropyl-1,3-thiazolidine-2-thione to five-membered N-acyl iminium ions.
abstract: [reaction: see text] Addition of the chlorotitanium enolate of N-acetyl 4-isopropyl-1,3-thiazolidine-2-thione to five-membered, N-substituted N-acyl iminium ions furnished the corresponding Mannich-type addition products with good diastereoselectivity and in good yields. The synthetic utility of the addition product 8 was demonstrated in a chemospecific anti-aldol reaction with cinnamaldehyde. By using this strategy, we constructed three contiguous chiral centers with high stereocontrol employing the same chiral auxiliary. X-Ray crystallographic analysis of addition product 2 and aldol product 14 revealed their absolute stereochemistry.
authors.affiliation: Division of Medicinal and Natural Products Chemistry, College of Pharmacy, The University of Iowa, Iowa City, Iowa 52242, USA.
authors.forename: Efraín
authors.initials: E
authors.lastname: Barragán
authors.forename: Horacio F
authors.initials: HF
authors.lastname: Olivo
authors.forename: Moisés
authors.initials: M
authors.lastname: Romero-Ortega
authors.forename: Seth
authors.initials: S
authors.lastname: Sarduy
mesh_terms: D007097:Imines / Q000737:chemistry*; D013237:Stereoisomerism; D013844:Thiazoles / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*
chemical_list: D007097:Imines; D013844:Thiazoles; D014025:Titanium