title: Unexpected insertion of CO2 into the pentacoordinate P-N bond: Atherton-Todd-type reaction of hydrospirophosphorane with amines.
abstract: The Atherton-Todd-type reaction of pentacoordinate hydrospirophosphoranes with amines was investigated, and a novel CO2 insertion reaction into the pentacoordinate P-N bond under mild conditions was developed. The mechanism and stereochemistry of the CO2 insertion reaction between hydrospirophosphoranes and secondary amines were proposed via a carbon-13 labeling experiment, a (31)P NMR tracing experiment, and X-ray diffraction analysis. The chlorinated spirophosphorane intermediate was first generated with stereoretention of the configuration at phosphorus and subsequently was attacked by a carbamate anion formed from CO2 and a secondary amine. It was found that rear attack of nucleophilic substitution with stereoinversion at pentacoordinate phosphorus was the preferred route, although front attack happened for sterically hindered reactants. The configuration of the CO2 insertion product depended mainly upon the original phosphorus configuration of the hydrospirophosphoranes.
authors.affiliation: The College of Chemistry and Molecular Engineering, The Key Laboratory of Chemical Biology and Organic Chemistry of Henan Province, Zhengzhou University , Zhengzhou, 450001 Henan, China.
authors.forename: Shuxia
authors.initials: S
authors.lastname: Cao
authors.forename: Peng
authors.initials: P
authors.lastname: Gao
authors.forename: Yanchun
authors.initials: Y
authors.lastname: Guo
authors.forename: Huamin
authors.initials: H
authors.lastname: Zhao
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.forename: Yifan
authors.initials: Y
authors.lastname: Liu
authors.forename: Yufen
authors.initials: Y
authors.lastname: Zhao
mesh_terms: D000588:Amines / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008968:Molecular Conformation; D010753:Phosphoranes / Q000737:chemistry*
chemical_list: D000588:Amines; D010753:Phosphoranes; D002245:Carbon Dioxide