The Synthesis Of α,α-dihalo Ketone And It's Reaction With Allylsamarium Bromide

The application of samarium reagents in organic synthesis has been attracted more attention. It benefits to develop further the high selective reaction by samarium reagents. The thesis consists of the following two sections.1. Compared to allylmagnesium bromide, allylsamarium bromide has much lower reactivity, and it does not give rise to coupling byproduct during preparation. Especially, it has excellent selectivity. A series ofα,α-dihalo ketones were prepared as substrate, and its reaction with allylsamarium bromide was carried out. The experiment showed that: (a) these reactions produce two kinds of unknown compounds containing different labile functional groups; (b) the products containing a carbon atom bearing three or four different labile functional groups, these compounds usually difficult to prepare, a one-pot method for preparation of this kind of compounds is developed; (c) allylsamarium bromide selectively attacks the carbonyl group; (d) allylsamarium bromide is added toα,α-dihalo ketones despite the steric hindrance; (e) a possible mechanism of the transformation is proposed.2. NaBrO3/NaHSO3 or KClO3/NaHSO3 system reacted with 1,3-dicarbonyl compounds is developed. A new method for halogenation of 1,3-dicarbonyl compounds is proposed.