Hydroboration Reactions with 6-Thia-nido-decaborane(11)

Article abstract of DOI:10.1021/ja00533a011

Alkenes and alkynes undergo a facile hydroboration reaction with 6-SB9H11.Alkenes give 9-R-6-SB9H10 products where R = alkyl.Those alkenes investigated were ethylene, 1-octene, cyclohexene, cyclopentadiene, styrene, and 1-methyl-1-cyclohexene.Alkynes give 9-R'-6-SB9H10 products where R' = alkenyl.In the cases of acetylene a double hydroboration occurs to give 9,9'-CH3CH-(6-SB9H10)2.Those alkynes investigated were acetylene, diphenylacetylene, phenylacetylene, and 3-hexyne.Attachment of the organic moiety to the 9 position of the 6-SB9H10 cage was established by 11B NMR.The 13C and 1H NMR spectra and mass spectra were also consistent with hydroboration.Oxidation of the organothiaboranes by alkaline peroxide gave the expected ketone or alcohol for most cases.The observation of trans-2-methylcyclohexanol after oxidation of the 1-methyl-1-cyclohexene hydroboration product indicates that the hydroboration is a regiospecific anti-Markownikoff syn addition.A possible mechanism is discussed.Pyrolysis (400-450 deg C) of the nido 9-R-6-SB9H10 molecules gives the corresponding closo derivative as a mixture of 2-, 6-, and 10-R-1-SB9H8 isomers.The interaction of aldehydes and ketones with 6-SB9H11 is more complex and involves degradative hydroboration.