title: Unusual reagent control of diastereoselectivity in the 1,2-addition of hard carbon nucleophiles to C(6)-heteroatom substituted cyclohexenones.
abstract: [reaction: see text] A surprising and synthetically useful counterion-dependent reversal of diastereoselectivity was found in 1,2-additions of hard carbon nucleophiles to C(6)-heterosubstituted cyclohexenones. In general, Grignard reagents added syn to the C(6)-substituent and Li reagents added anti, although some exceptions were found. Selectivities could be increased in some cases by appropriate choice of solvent and/or cosolvent.
authors.affiliation: Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701, USA.
authors.forename: H A
authors.initials: HA
authors.lastname: Lindsay
authors.forename: C L
authors.initials: CL
authors.lastname: Salisbury
authors.forename: W
authors.initials: W
authors.lastname: Cordes
authors.forename: M C
authors.initials: MC
authors.lastname: McIntosh
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry; D002227:Carbazoles; D003512:Cyclohexanones / Q000737:chemistry; D004224:Diterpenes; D006844:Hydrocarbons, Cyclic / Q000737:chemistry*; D007211:Indoles / Q000737:chemistry; D008094:Lithium / Q000737:chemistry; D017616:Magnesium Compounds / Q000737:chemistry; D008968:Molecular Conformation; D015394:Molecular Structure; D011758:Pyrroles / Q000737:chemistry; D013141:Spiro Compounds / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D002227:Carbazoles; D003512:Cyclohexanones; D004224:Diterpenes; D006844:Hydrocarbons, Cyclic; D007211:Indoles; D017616:Magnesium Compounds; D011758:Pyrroles; D013141:Spiro Compounds; C447979:brevione A; C078290:manzamine A; D008094:Lithium