Nitrogen-containing remote functionalised organolithium compounds by reductive opening of five- and six-membered heterocycles

The reaction of different five- or six-membered nitrogen-containing heterocycles such as N-isopropyl-2-phenylpyrrolidine (1), N-phenyl-3-pyrroline (6), N-phenylisoindoline (10), N-phenyltetrahydroisoquinoline (13) and N-methyltetrahydroisoquinoline (19) with an excess of lithium powder and a catalytic amount of DTBB (4.5 mol %), followed by treatment with electrophiles [H2O, D2O, MeI, CH2=CHCH2Br, (PrCHO)-C-i, Bu(t)CHO, PhCHO, Me(2)CO, Pr(n)COMe, PhCOMe, (CH2)(4)CO, (CH2)(5)CO, CO2] and final hydrolysis gives a wide series of functionalised amines 3, 8, 9, 12 and 19, the key step in the process, being the reductive opening of the starting material giving a dianionic remote functionalised organolithium compound. (C) 1996 Elsevier Science Ltd