The synthesis of polysubstituted furansl appears especially worthy of study because they are important building blocks for natural and non-natural product syntheses.2 However, the propensity of furans to undergo both metallation and elec- trophilic reaction at carbon-2 or carbon-53 has inspired a ... .i. 3,4-Disubstituted furans: Part 2. Part 1: M. S. Ho and HNC Wong, J. Chern. SOC., Chem. Comrnun., 1989, 1238. ... Published on 01 January 1992. Downloaded by ...