1: 1.) DMAP, DMAP*HCl, 2.) DCC / 1.) r.t., 5 min, 2.) r.t., 8 h 2: 1.) n-BuLi, 2.) oxalic acid / 1.) THF, hexane, -60 deg C, 30 min; -95/-90 deg C, 60 min, 2.) THF, -95/-90 deg C, 30 min View Scheme

n-butyllithium; oxalic acid 1.) THF, hexane, -60 deg C, 30 min; -95/-90 deg C, 60 min, 2.) THF, -95/-90 deg C, 30 min; Yield given. Multistep reaction;

(i) THF, (ii) /BRN= 102415/; Multistep reaction;