Alkane functionalization on a preparative scale by mercury-photosensitized cross-dehydrodimerization

Journal Article · Wed Apr 12 00:00:00 EDT 1989 · Journal of the American Chemical Society; (USA)

DOI:https://doi.org/10.1021/ja00190a032· OSTI ID:7071152

Brown, S H; Crabtree, R H ^[1]

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1. Yale Univ., New Haven, CT (USA)

Alkanes can be functionalized with high conversions and in high chemical and quantum yields on a multigram scale by mercury-photosensitized reaction between an alkane and alcohols, ethers, or silanes to give homodimers and cross-dehydrodimers. The separation of the product mixtures is often particularly easy because of the great difference in polarity of the homodimers and cross-dimers. It is also possible to bias the product composition when the ratio of the components in the vapor phase is adjusted by altering the liquid composition. This is useful either to maximize chemical yield or to ease separation by favoring the formation of the most easily separated pair of compounds. The mechanistic basis of the reaction is discussed and a number of specific types of syntheses, for example of 2,2-disubstituted carbinols, are described in detail. The selectivity of cross-dimerization is shown to exceed that for homodimerization and reasons are discussed. Relative reactivities of different compounds and classes of compound are MeOH < p-dioxane < cyclohexane < 1,3,5-trioxacyclohexane < ethanol < isobutane < THF < Et{sub 3}SiH. The observed selectivities generally parallel those for homodimerization, reported in the preceding paper, but certain differences are noted, and reasons for the differences are proposed. The bond-dissociation energy of Et{sub 3}SiH is estimated from the reactivity data to be 90 kcal/mol. Eleven new carbinols are synthesized. 39 refs., 6 tabs.

• OSTI ID: 7071152
• Journal Information: Journal of the American Chemical Society; (USA), Journal Name: Journal of the American Chemical Society; (USA) Vol. 111:8; ISSN 0002-7863; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical &amp; Physicochemical Properties
400500 -- Photochemistry
ALCOHOLS
ALKANES
CHEMICAL REACTIONS
CHEMISTRY
DATA
ETHERS
EXPERIMENTAL DATA
HYDRIDES
HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
INFORMATION
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
ORGANIC SILICON COMPOUNDS
PHOTOCHEMISTRY
SILANES
SILICON COMPOUNDS