title: Carbanion-accelerated Claisen rearrangements: asymmetric induction with chiral phosphorus-stabilized anions.
abstract: The carbanion-accelerated Claisen rearrangement has been extended to include phosphorus carbanion-stabilizing groups. The appropriately substituted allyl vinyl ethers are synthesized by the nucleophilic addition of allyl oxides to phosphorus-substituted allenes, which are obtained in one step from simple starting materials. The phosphorus-stabilized, carbanion-accelerated Claisen rearrangements proceed rapidly at room temperature in high yield, and the rearrangements are highly site- and stereoselective. The first examples of asymmetric induction in the Claisen rearrangement with chiral, phosphorus, anion-stabilizing groups are described. The observed asymmetric induction is highly dependent on the structure of the auxiliary and the metal counterion involved. Both internal and relative diastereoselectivity are high. A model for the observed sense of internal diastereoselectivity is proposed that is founded in the current understanding of the structure of phosphorus-stabilized anions.
authors.affiliation: Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, Illinois 61801, United States. sdenmark@illinois.edu
authors.forename: Scott E
authors.initials: SE
authors.lastname: Denmark
authors.forename: John E
authors.initials: JE
authors.lastname: Marlin
authors.forename: G
authors.initials: G
authors.lastname: Rajendra
mesh_terms: D000498:Allyl Compounds / Q000737:chemistry*; D000838:Anions / Q000737:chemistry*; D002384:Catalysis; D015394:Molecular Structure; D010758:Phosphorus / Q000737:chemistry*; D013237:Stereoisomerism; D014753:Vinyl Compounds / Q000737:chemistry*
chemical_list: D000498:Allyl Compounds; D000838:Anions; D014753:Vinyl Compounds; D010758:Phosphorus; C100195:vinyl ether