The metal derivatives 2-5, derived from the protected 4-bromo-2-furancarbaldehydes 1a,b, were reacted with the bifunctional reagent 6 bearing an aldehyde and an ester function. Whereas the Li-, Mg- and Zn-species turned out to be either unselective and/or too unreactive, the Ti-derivatives 5a,b gave the addition products 7a,b in good yield and with high chemoselectivity.
使衍生自受保护的
4-溴-2-呋喃甲醛1a,b的
金属衍
生物2-5与带有醛和酯官能团的双官能试剂6反应。Li,Mg和Zn种类要么是非选择性的和/或太不活泼的,而Ti衍
生物5a,b则以高收率和高
化学选择性提供了加成产物7a,b。