冠醚-CuI混合催化剂的组份对溴代雌甾的亲核取代反应的影响

冠醚能与碱或盐的阳离子络合,从而使阴离子在非质子溶剂中成为“裸阴离子”,具有特别强的亲核性或硷性,所以在有机合成中获得广泛的应用。为了探求冠醚的应用范围,同时寻求一种既简便又宜于较大量制备雌甾甲氧基衍生物的方法,作者曾首次将冠醚用于雌甾衍生物的合成,设计了冠醚-亚铜盐混合催化体

Effect of Components of Crown-CuI Mixed Catalyst on Nucleophilic Substitution of Bromoestrogen

Crown ethers have the unique property to form stable complexes with metal ions making the counterparts bare anions in aprotic solvents. Anions in such a state have extre- mly strong nucleophilicity and/or basicity. We have previously devised, for the first time, the synthesis of steroid using the crown ether-cuprous salt mixed catalytic system. Applica- tion of such a system to estrogenic steroid synthesis has effected efficient etherification to give di- and monomethyl phenolic ether of estrogenic steroid in excellent yield. In view of the fact that the stability of the complex depends mainly on match of the size of the sodium cation with the cavity of the crown ethers. Experimental results indica- ted that benzo-15-crown-5 in DMF with NaOCH_3 as base is the most effective catalyst and CuI as cocatalyst also plays an important role in such a catalytic reaction.