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[摘要]：A review. Novel catalytic reactions via ruthena- or rhodacyclic intermediates have been developed by our research group. We initiated our study from (1) ruthenium-catalyzed [2 + 2] cycloaddn. of alkynes with alkenes, followed by developing (2) intramol. Pauson-Khand-type reaction of 1,6-enynes, (3) hydroquinone synthesis, (4) cyclocotrimerization reactions, and (5) codimerization of styrenes with ethylene. Another approach to construct novel functional monomers, such as cyclopentenones, pyranopyrandiones, and substituted phenols, involves cleavage of carbon-carbon bonds in cyclobutenediones, cyclopropenones, and cyclobutenones. All reactions may proceed with high atom-efficiency via ruthena- or rhodacyclic intermediates, represented by ruthenacyclopentene, (maleoyl)ruthenium, and rhodacyclopentenone intermediates. In addn., rhodium-catalyzed [2 + 2 + 2] cocylization of alkynes with isocyanates as well as novel ruthenium-catalyzed [2 + 2 + 1] cocyclization of alkynes, isocyanates, and carbon monoxide have been disclosed. |
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