Iron and ruthenium Lewis acid catalyzed asymmetric 1,3-dipolar cycloaddition reactions between nitrones and enals.
The single coordination-site transition metal Lewis acids [CpM(BIPHOP-F)][SbF6] (M = Fe, Ru) catalyze the [3+2] dipolar cycloaddition reaction between reactive nitrones and alpha,beta-unsaturated aldehydes to give chiral isoxazolidines with ee values of 75 to >96%. The stereochemistry of the major enantiomer is consistent with an endo approach of the nitrone to the Calpha-Si-face of the enal in the s-trans conformation in the (R,R)-catalyst site. The absolute configuration is based on an X-ray structure determination.
Viton
Florian
F
University of Geneva, Department of Organic Chemistry, CH-1211 Geneva 4, Switzerland.
Bernardinelli
Gérald
G
Kündig
E Peter
EP
D000171:Acrolein / Q000031:analogs & derivatives* / Q000737:chemistry; D002384:Catalysis; D007501:Iron / Q000737:chemistry*; D007555:Isoxazoles / Q000138:chemical synthesis*; D008958:Models, Molecular; D009589:Nitrogen Oxides / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*; D013237:Stereoisomerism
D007555:Isoxazoles; D009589:Nitrogen Oxides; D009942:Organometallic Compounds; C015388:nitrones; D000171:Acrolein; D012428:Ruthenium; D007501:Iron