title: A reductive cyclization approach to attenol A.
abstract: A reductive cyclization strategy was applied to the synthesis of attenol A. This nontraditional approach to the spiroacetal structure illustrated several advantages of the reductive cyclization methodology. The attenol A core was formed in a carbon-carbon bond coupling that gave rise to a previously inaccessible spiroacetal epimer, a new method to synthesize thioketene acetals from a phenyl sulfone was realized, and the configurational stability of a nonanomeric spiroacetal was evaluated. A minor byproduct in the reductive cyclization reaction was identified that for the first time allowed direct evaluation of the stereoselectivity in a reductive cyclization of a dialkyloxy alkyllithium reagent.
authors.affiliation: Department of Chemistry, 1102 Natural Sciences II, University of California-Irvine, Irvine, California 92697-2025, USA.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: La Cruz
authors.forename: Scott D
authors.initials: SD
authors.lastname: Rychnovsky
mesh_terms: D000080:Acetals / Q000737:chemistry; D003500:Cyclization; D004952:Esters / Q000737:chemistry; D004988:Ethers, Cyclic / Q000138:chemical synthesis* / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008094:Lithium / Q000737:chemistry; D015394:Molecular Structure; D010084:Oxidation-Reduction; D013237:Stereoisomerism
chemical_list: D000080:Acetals; D004952:Esters; D004988:Ethers, Cyclic; C423354:attenol A; D008094:Lithium