Pinacol coupling of cycloalkanones
Document Type Dissertation/Thesis
A pinacol is a compound having two hydroxyl groups on adjacent carbons. They can be made very easily from carbonyl compounds usmg three different methods. Each method uses a different metal complex: (1) AI-Hg in benzene, (2) Mg-Hg and TiCl4. and (3) SmI2. Not much is known about the specifics of the mechanism of the coupling. For this reason it is unknown if statistical ratios should be expected when forming pinacols from cycloalkanones. In the mixed coupling three different products are formed. It was hypothesized, based in poor work with Ti mediated coupling, that with the AI-Hg in benzene protocol there should be no statistical ratios of the products of the mixed coupling. Three different systems were studied: cyclopentanone coupled to cyclohexanone (5-6 ring system), cyclopentanone coupled to cycloheptanone (5-7 ring system), and cyclohexanone coupled to cycloheptanone (6-7 ring system). The statistics of this would be an expected 1-2-1 ratio of products, with the mixed pinacol in greatest amount.