An investigation of the Lewis acid mediated 1,3-dipolar cycloaddition between N-benzyl-C-(2-pyridyl)nitrone and allylic alcohol. Direct entry to isoxazolidinyl C-nucleosides.
The cycloaddition reaction of N-benzyl C-(2-pyridyl) nitrone with allylic alcohol has been carried out to obtain the corresponding 2-benzyl-3-(2-pyridyl)-5-hydroxymethylisoxazolidine. The influence of Lewis acids in the reaction has been studied and a complete 3,5-regioselectivity and cis diastereoselectivity was observed when the reaction was carried out with 1.0 equiv of AgOTf, [Ag(OClO3)(PPh2Me)] or Zn(OTf)2. Insight into the mechanism of the reaction has been obtained by isolating and characterizing (X-ray) the intermediate complexes. Also, a model based on both experimental and theoretical results is proposed.
Merino
Pedro
P
Departamento de Quimica Organica Facultad de Ciencias, ICMA, Universidad de Zaragoza, CSIC, E-50009 Zaragoza, Aragon, Spain. pmerino@posta.unizar.es
Tejero
Tomas
T
Laguna
Mariano
M
Cerrada
Elena
E
Moreno
Ana
A
Lopez
Jose A
JA
D000143:Acids / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D003500:Cyclization; D007555:Isoxazoles / Q000138:chemical synthesis*; D008956:Models, Chemical; D015394:Molecular Structure; D009589:Nitrogen Oxides / Q000138:chemical synthesis* / Q000737:chemistry; D009705:Nucleosides / Q000138:chemical synthesis*; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry; D010084:Oxidation-Reduction; D020005:Propanols / Q000737:chemistry*; D015203:Reproducibility of Results; D013237:Stereoisomerism; D013997:Time Factors
D000143:Acids; D007555:Isoxazoles; D009589:Nitrogen Oxides; D009705:Nucleosides; D009942:Organometallic Compounds; D020005:Propanols; C015388:nitrones; C006463:allyl alcohol