Synthesis of ferrocene substituted dihydrofuran derivatives via manganese(III) acetate mediated radical addition-cyclization reactions

In this study, the manganese(III) acetate mediated radical addition-cyclization reactions of ferrocene substituted alkenes and active methylene compounds were carried out. The regio- and stereoselective radical cyclization reactions of (E)-styrylferrocene (1a) and active methylene compounds (2a-g) gave trans-5-ferrocenyl-4-phenyl-4,5-dihydrofuran compounds as the sole products. The reactions of 1-ferrocenyl-1-aryl(heteroaryl)ethenes (1b-e) and active methylene compounds (2a-f) via Mn(OAc)(3) led to furan and benzofuran derivatives (10-33) in mid-good yields (up to 75%). Surprisingly, ferrocene substituted allylidene derivatives were obtained from the Mn(OAc)(3) mediated reactions of 1-aryl-1ferrocenylethene (lb-d) and 1,3-dimethylbarbituric acid (2g). The uses of ferrocene substituted alkenes in manganese(III) acetate mediated radical reactions is the first example in this field as far as we know. (C) 2017 Elsevier Ltd. All rights reserved.