title: Simple enantioselective approach to synthetic limonoids.
abstract: An enantioselective and short approach to the synthesis of limonoids has been applied successfully to the simplest limonoid, 2. The carbon atoms of the tetracyclic framework were assembled in a single operation from the acylsilane 3 and the acetylenic sulfone 4 to form the chiral epoxide 5. Successive cationic and free-radical cyclizations starting with 5 generated the tetracyclic intermediates 9a, which was transformed into limonoid 2 by a sequence consisting of (1) oxidative cleavage of the exocyclic double bond, (2) stereoselective alpha-methylation, (3) furyl attachment, and (4) introduction of a 16-keto function.
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Behenna
authors.forename: E J
authors.initials: EJ
authors.lastname: Corey
mesh_terms: D000480:Alkynes / Q000737:chemistry; D003500:Cyclization; D004852:Epoxy Compounds / Q000138:chemical synthesis / Q000737:chemistry; D036701:Limonins / Q000138:chemical synthesis*; D008745:Methylation; D012821:Silanes / Q000737:chemistry; D013237:Stereoisomerism; D013450:Sulfones / Q000737:chemistry
chemical_list: D000480:Alkynes; D004852:Epoxy Compounds; D036701:Limonins; D012821:Silanes; D013450:Sulfones