Abstract
Square planar cationic rhodium(I) dicarbonyl complexes [{Rh((mim)2CH2)(CO)2}+BPh - 4] (1) and [{Rh((mBnzim)2CH2)-(CO)2}+BPh - 4] (2) [mim = N-methylimidazol-2-yl, mBnzim = N-methylbenzimidazol-2-yl] are catalysts for the cyclisation of alkynoic acids to lactones. The unsaturated acids, 4-pentynoic acid, 4-hexynoic acid and 5-hexynoic acid were cyclised to γ-methylene-γ-butyrolactone, E-5-ethylidenetetrahydro-2-furanone and 6-methylidenetetrahydo-2-pyrone, respectively. Cyclisation of 4-hexynoic acid proceeds stereoselectively with exclusive formation of the E-isomer of 5-ethylidenetetrahydro-2-furanone. Complexes 1 and 2 also catalyse cyclisation of acetylenic alcohols to oxygen-containing heterocycles.
Original language | English |
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Pages (from-to) | 97-104 |
Number of pages | 8 |
Journal | Journal of Organometallic Chemistry |
Volume | 607 |
Issue number | 1-2 |
Publication status | Published - 11 Aug 2000 |
Externally published | Yes |