Keith E. McCarthy

More highly mixed, higher order cyanocuprates “RT(2-thienyl)Cu(CN)Li2”. Efficient reagents which promote selective ligand transfer

Abstract The combination of an organolithium (R T Li) and 2-lithiothiophene (2-thienyl) with CuCN forms a new reagent, “R T (2-thienyl)Cu(CN)Li 2 .” This species selectively transfers the R T ligand in substitution reactions with epoxides and halides. In conjugate addition processes, the cuprate reacts with unhindered substrates, while β,β-disubstituted cases unexpectedly afford products resulting from 1,2-addition of the thiophene group. The prospects for use of these reagents in the synthesis of polyene macrolide antibiotics are discussed.

Reactions of stoichiometric higher order, mixed lithio magnesio organocuprates

Abstract Novel higher order cuprates, R(2-thienyl)Cu(CN)LiMgBr (2), are prepared from the 1:1:1 combination of CuCN, 2-lithiothiophene and RMgX. Reactions of various members of this new class of reagents are described, including substitution and conjugate addition processes, where the ligand derived from the Grignard reagent is selectively transferred. The effects of added BF3.Et2O are discussed. Some comparison reactions with the corresponding lower order reagents, RCu(CN)MgBr, have also been carried out. Evidence is presented suggesting that species 2, unlike their dilithio analogs, are not discrete.

Alkylation of the cyclic sulfamate of prolinol. Preparation of optically active 2-alkyl-substituted pyrrolidines

Abstract Treatment of the cyclic sulfamate of (R)-prolinol ( 1 ) with aromatic lithium reagents, followed by acidic hydrolysis, gives 2-substituted pyrrolidines 3a-c in moderate yields.

Heterocycles in synthesis. Dipeptides via unmasking of 5-acyl- and 5-acyloxyaminooxazoles

Abstract Heteroaromatic oxazole rings, when sibstituted in the appropriate fashion, may be unsmasked to afford dipeptides in excellent yields.