Michael J. Mealy

Synthesis of heterocycles by cyclization of unsaturated organolithiums: a review

The preparation of oxygen and nitrogen containing heterocyclic compounds by cyclization of unsaturated organolithium compounds has been reviewed. The review contains 57 references to relevant literature through early 2001.

Preparation of differentially 1,3-disubstituted indolines by intramolecular carbolithiation

Abstract The ether-soluble dilithio species ( 2 ), derived from N-allyl-2-bromoaniline ( 1 ) upon treatment with t-BuLi at −78°C, cyclizes when warmed to +5°C in the presence of TMEDA to give a (1-lithio-3-indolinyl)methyllithium ( 3 ) that may be differentially functionalized by sequential addition of electrophiles. The cyclization of 2 to 3 proceeds enantioselectively when conducted in the presence of (1S,2S)-(+)-N,O-dimethylpseudoephedrine.

Asymmetric intramolecular carbolithiation of achiral substrates: synthesis of enantioenriched (R)-(+)-cuparene and (R)-(+)-herbertene.

Concise syntheses of the sesquiterpenes (R)-(+)-cuparene and (R)-(+)-herbertene by asymmetric cyclization of achiral olefinic alkyllithium precursors in the presence of (-)-sparteine are reported. The quaternary stereogenic center in each product is set at the final step of the synthesis by enantioselective (er = 61:39) 5-exo ring closure.