Polarity Matching of Radical Trapping: High Yielding 3-exo and 4-exo Cyclizations
作者:Andreas Gansäuer、Thorsten Lauterbach、Daniel Geich-Gimbel
DOI:10.1002/chem.200400685
日期:2004.10.18
and cyclobutanes via radical chemistry is described. The method that generally proceeds in high yields uses epoxides as radical precursors and titanocene(III) complexes as the electron transfer catalysts (see scheme). The key to the success of the transformation is constituted by the chemoselectivity of radical reduction. Electrophilic enol radicals generated through cyclization are reduced rapidly
描述了通过自由基化学催化合成环丙烷和环丁烷。通常以高收率进行的方法使用环氧化物作为自由基前体,并使用钛茂(III)配合物作为电子转移催化剂(参见方案)。转化成功的关键在于自由基还原的化学选择性。通过环化产生的亲电子烯醇基团迅速减少,而其前体亲核烷基团则不受影响。