Abstract
Photolysis of dimanganese decacarbonyl [Mn-2(CO)(10)] using visible light produces the manganese pentacarbonyl radical [Mn-.(CO)(5)] which reacts with organohalides to form carbon-centred radicals. Efficient halogen-atom abstraction occurs with allylic or benzylic halides or polyhalogenated precursors bearing a weak carbon-halogen bond. Steric interactions are also important and primary halides generally react much faster with Mn-.(CO)(5) than secondary or tertiary halides. The carbon-centred radicals can undergo efficient dimerisation or, in the presence of an acceptor double bond, cyclisation to form 5-membered rings. Cyclisation of terminal alkenes leads to primary radicals, which can then react by iodine- or bromine-atom transfer or, on addition of propan-2-ol, hydrogen-atom transfer. Hydroxylamines can also be formed when cyclisation reactions are carried out in the presence of TEMPO. These high-yielding cyclisation-trapping reactions are initiated under mild reaction conditions and the manganese halide by-products [of type XMn(CO)(5)] can be easily separated from products by a simple DBU work-up procedure.
| Original language | English |
|---|---|
| Pages (from-to) | 1187-1194 |
| Number of pages | 8 |
| Journal | Journal of the Chemical Society-Perkin Transactions 1 |
| Issue number | 8 |
| Publication status | Published - 2000 |
Keywords
- CYCLIZATION REACTIONS
- ALKYLATION SUBUNITS
- ATOM TRANSFER
- 1,6-DIENES
- CARBONYL
- CC-1065
- LACTAMS
- CATION
- BONDS
- CBI