Enantioselective Synthesis of 3-Substituted Indolines by Asymmetric Intramolecular Carbolithiation in the Presence of (−)-Sparteine

Experimental 'procedure Typical procedure for the enantioselective carbolithiation. Synthesis of (3R)-1-Benzyl-3-methyl-2,3-dihydro-lH-indol 1 3a A solution of N-Allyl-N-benzyl-2-bromoaniline (302 mg, I mmol) in dry toluene (hnl) was added dropwise at-90°C to a solution of tBuLi / hexane (1.3 ml, 2.2 mmol) in presence of (_)_ sparteine (235 Ill, 1.5 mmol) in dry toluene (8 ml). After 18h at-90°C MeOH (1 ml) was added and the reaction mixture was poured into NHtCI sat. The organic phase was dried over MgS04 and after evaporation of the solvent the residue was chromatographed on silical gel. (eluent: petrolether / toluene: 4/1 containing a few drops of32% NH 3). Yield 85% (190 mg); Synthesis of