title: Solution structures of the mixed aggregates derived from lithium acetylides and a camphor-derived amino alkoxide.
abstract: Low-temperature (6)Li, (13)C, and (15)N NMR spectroscopies reveal that mixtures of lithium cyclopropylacetylide or lithium phenylacetylide (RCCLi) and a vicinal amino alkoxide derived from camphor (R*OLi) in THF/pentane afford an asymmetric (RCCLi)(3)(R*OLi) mixed tetramer and a C(2)-symmetric (RCCLi)(2)(R*OLi)(2) mixed tetramer depending on the stoichiometries. The corresponding (RCCLi)(R*OLi)(3) mixed tetramer is not observed. R*OLi-mediated additions of PhCCLi to benzaldehyde proceed with up to an 8:1 enantiomeric ratio that depend on both the choice of R*OLi and the PhCCLi/R*OLi stoichiometries. The results are considered in light of a previously proposed mechanism for the 1,2-addition to a trifluoromethyl ketone.
authors.affiliation: Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, NY 14853-1301, USA.
authors.forename: T F
authors.initials: TF
authors.lastname: Briggs
authors.forename: M D
authors.initials: MD
authors.lastname: Winemiller
authors.forename: B
authors.initials: B
authors.lastname: Xiang
authors.forename: D B
authors.initials: DB
authors.lastname: Collum
mesh_terms: D002164:Camphor / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*; D018020:Lithium Compounds / Q000737:chemistry*
chemical_list: D007659:Ketones; D018020:Lithium Compounds; D002164:Camphor