title: Application of a new chiral phosphepine to the catalytic asymmetric synthesis of highly functionalized cyclopentenes that bear an array of heteroatom-substituted quaternary stereocenters.
abstract: Through the design and synthesis of a new chiral phosphepine, the first catalytic asymmetric method for the [3 + 2] cycloaddition of allenes with olefins has been developed that generates cyclopentenes that bear nitrogen-, phosphorus-, oxygen-, and sulfur-substituted quaternary stereocenters. A wide array of racemic γ-substituted allenes can be employed in this stereoconvergent process, which occurs with good enantioselectivity, diastereoselectivity, regioselectivity, and yield. Mechanistic studies, including a unique observation of a (modest) kinetic resolution of a racemic allene, are consistent with addition of the phosphepine to the allene being the turnover-limiting step of the catalytic cycle.
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Fujiwara
authors.forename: Gregory C
authors.initials: GC
authors.lastname: Fu
mesh_terms: D002384:Catalysis; D018360:Crystallography, X-Ray; D003500:Cyclization; D003517:Cyclopentanes / Q000138:chemical synthesis* / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D010720:Phosphines / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D003517:Cyclopentanes; D010720:Phosphines