1: 91 percent / N,N,N',N'-tetramethylene diamine, n-C4H9Li / tetrahydrofuran / -60 °C 2: 1) H2SO4, 2) nC4H9Li / 1) water, THF, RT, 2) THF, -6 deg C View Scheme

n-butyllithium; sulfuric acid 1) water, THF, RT, 2) THF, -6 deg C; Yield given. Multistep reaction;