Solution structures and reactivities of the mixed aggregates derived from n-butyllithium and vicinal amino alkoxides.
Low-temperature (6)Li, (13)C, and (15)N NMR spectroscopies reveal that mixtures of n-BuLi and (1R,2S)-R'(2)NCH(R)CH(Ph)OLi (ROLi; R = Ph or Me; R'(2)N = pyrrolidino or Me(2)N) in THF/pentane afford a (n-BuLi)(3)(ROLi) (3:1) mixed tetramer and a C(2)-symmetric (n-BuLi)(2)(ROLi)(2) (2:2) mixed tetramer depending on the proportions of the reactants. The corresponding (n-BuLi)(ROLi)(3) (1:3) mixed tetramer is not observed. ROLi-mediated additions of n-BuLi to benzaldehyde proceed with up to 21:1 enantiomeric ratios that depend on the n-BuLi/ROLi stoichiometries. The enantioselectivities are considered in light of a previously posited mechanism involving reaction via the C(2)-symmetric 2:2 mixed tetramer.
Sun
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Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA.
Winemiller
M D
MD
Xiang
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B
Collum
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DB
D000480:Alkynes; D001547:Benzaldehydes / Q000737:chemistry; D048588:Benzoxazines; D003521:Cyclopropanes; D004852:Epoxy Compounds / Q000737:chemistry; D008094:Lithium / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D010078:Oxazines / Q000737:chemistry; D018894:Reverse Transcriptase Inhibitors / Q000737:chemistry; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
D000480:Alkynes; D001547:Benzaldehydes; D048588:Benzoxazines; D003521:Cyclopropanes; D004852:Epoxy Compounds; D009942:Organometallic Compounds; D010078:Oxazines; D018894:Reverse Transcriptase Inhibitors; C434823:n-butyllithium; D008094:Lithium; C098320:efavirenz; C032175:benzaldehyde