Journal of the American Chemical Society, 124(2), 264-271 (2002-01-10)
6Li and (13)C NMR spectroscopic studies were carried out on [(6)Li]n-BuLi and [(6)Li]PhLi (RLi) in toluene-d(8) containing the following diamines: N,N,N',N'-tetramethylethylenediamine (TMEDA), N,N,N',N'-tetraethylethylenediamine, 1,2-dipyrrolidinoethane, 1,2-dipiperidinoethane, N,N,N',N'-tetramethylpropanediamine, trans-(R,R)-N,N,N',N'-tetramethylcyclohexanediamine, and (-)-sparteine. Dimers of general structure (RLi)(2)S(2) (S = chelating diamine) are formed
[reaction: see text] The "Southern Hemisphere" intermediate 2, used by Masamune and co-workers for their asymmetric total synthesis of bryostatin 7 (1), has been synthesized from (E)-1,4-hexadiene (11) by a 24-step pathway that has a longest linear sequence of only
Enantioselective total synthesis of the marine toxin (-)-gymnodimine employing a Barbier-type macrocyclization.
Ke Kong et al.
Angewandte Chemie (International ed. in English), 48(40), 7402-7405 (2009-09-04)
A diamine-free protocol for the s-BuLi-mediated lithiation-trapping of N-Boc heterocycles has been developed. In the optimized procedure, lithiation is accomplished using s-BuLi in THF at -30 °C for only 5 or 10 min. Subsequent electrophilic trapping or transmetalation-Negishi coupling delivered
The Journal of organic chemistry, 68(16), 6387-6391 (2003-08-05)
The effects of lithium dialkylamide structure, mixed aggregate formation, and solvation on the stereoselectivity of ketone enolization were examined. Of the lithium dialkylamides examined, lithium tetramethylpiperidide (LiTMP) in THF resulted in the best enolization selectivity. The stereoselectivity was further improved
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