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Trialkylboranes prepared from alkenes viahydroboration react with lead(IV) acetate azide in dichloromethane at −25 °C to form the corresponding azidoalkanes in a one-pot manner. One or two of the alkyl groups of trialkylboranes are utilized in the reaction. For example, 1-azidohexane is afforded from 1-hexene in 50% yield based on the alkene employed.

The reaction of 1,2-bis(trimethylsilyl)ethyne with a stoichiometric amount of dialkylborane proceeds to the monohydroboration stage, giving [(Z)-1,2-bis(trimethylsilyl)ethenyl]dialkylborane. In situ treatment of the above alkenylborane with iodine in the presence of aqueous sodium hydroxide provides highly pure (E)-1-alkyl-1,2-bis(trimethylsilyl)ethene whose alkyl group migrates from the boron atom. Successive treatment of [(Z)-1,2-bis(trimethylsilyl)ethenyl]dicyclohexylborane with copper(I) iodide, allyl bromide, and aqueous sodium hydroxide affords a cross-coupling product, (Z)-1,2-bis(trimethylsilyl)-1,4-pentadiene, stereoselectively. A similar cross-coupling reaction with 1-bromo-1-hexyne followed by UV irradiation affords (E)-1,2-bis(trimethylsilyl)-1-octen-3-yne stereoselectively.

Mixed trialkylboranes, prepared by the successive reactions of BH3in THF with a sterically hindered internal olefin and a terminal olefin, reacted with either aqueous ferric thiocyanate or aqueous ferric selenocyanate to give corresponding secondary or tertiary alkyl thiocyanates or selenocyanates selectively.

Trialkylboranes, prepared by hydroboration of terminal or internal olefins, react with ferric selenocyanate in an aqueous tetrahydrofuran to give corresponding primary or secondary alkyl selenocyanates.

The reaction of trialkylboranes, prepared from olefin via hydroboration, with selenium dioxide was studied. In the aqueous selenium dioxide solution, trialkylboranes give the mixtures of dialkyl selenide and dialkyl diselenide, whereas in the suspension of selenium dioxide in tetrahydrofuran, trialkylboranes give dialkyl selenides selectively under the condition where the reaction time and the amount of selenium dioxide are controlled.

The successive treatment of 3-chloro-1-trimethylsilylpropyne with dialkylboranes and aqueous sodium hydroxide provided (E)-1-alkyl-1-trimethylsilylpropenes whose alkyl groups were derived from a terminal or internal alkene viadialkylboranes.

Internal alkenyldialkylboranes give regio- and stereospecifically designed 1,4-dienes or conjugated enynes, bearing a substituent at the internal alkenyl carbon atom, by a coupling reaction with allyl bromide or 1-bromo-1-alkynes.

Trialkylboranes initiated the chlorinations of alkanes with radical chlorinating agents such as chlorine, t-butyl hypochlorite and N-chlorosuccinimide. The reactions proceeded at 20 °C even in the dark giving monochloroalkanes.

Internal enynyldialkylboranes give regio- and stereospecifically designed conjugated enynes, bearing an allyl or 1-alkynyl group on the internal alkenyl carbon atom, by a coupling reaction with allyl bromide or 1-bromo-1-alkynes.

In the reaction of trialkylborane with 1-alkyne and lead(IV) acetate in hexane, one of the alkyl groups of trialkylborane migrated to the terminal carbon atom of the triple bond, giving regiospecifically an internal enol acetate and an internal alkyne as the main reaction products. The former compound had (Z)-configuration.

Internal conjugated (E)-enynyldialkylboranes were synthesized by successive reactions of 1-iodo-1-alkynes with dialkylboranes and 1-alkynyllithiums in 31–79% yields. (E)-Enynyldialkylboranes, thus obtained, gave regio- and/or stereospecifically defined corresponding conjugated alkynones by alkaline hydrogen peroxide oxidation, conjugated (E)-enynes by protonolysis with acetic acid, and conjugated enynes bearing an unsaturated group on the internal alkenyl carbon atom by bis(acetylacetonato)copper-catalyzed cross-coupling reaction with allyl bromide or 1-bromo-1-hexyne respectively.

Alkanes were chlorinated with iodobenzene dichloride in the presence of the catalytic amount of trihexylborane almost quantitatively based on iodobenzene dichloride employed. Chlorine atom was introduced in a highly selective manner into the internal carbon atom of alkanes.

Treatment of 1-bromo-1-alkenyldialkylboranes with lead(IV) acetate or iodosobenzene diacetate afforded 1-bromo-1,2-dialkylethylenes in moderate yields. Furthermore, both E-isomers and Z-isomers could be independently obtained as the main products by the use of different reaction conditions.

In the reaction of trialkylborane with lead(IV) acetate or phenyliodoso acetate in benzene, about two thirds of the alkyl groups of trialkylborane were converted to the corresponding alkyl acetate without any isomerization of the alkyl group. Lead(IV) acetate reacted preferentially with the secondary alkyl group, while phenyliodoso acetate reacted only with the primary alkyl group. In either reaction, one mole of oxidizing agent was consumed for the formation of one mole of alkyl acetate.

The reaction of (1-halo-1-alkenyl)dialkylboranes with lead(IV) acetate or (diacetoxyiodo)benzene was studied. (1-Bromo-1-alkenyl)dialkylboranes gave 1-bromo-1,2-dialkylethylenes. When alkyl groups on the boron atom of vinylboranes were bulky or the reaction temperatures were low, Z-isomers were afforded, whereas when alkyl groups on the boron atom were small or the reaction temperatures were relatively high, E-isomers were afforded as the main products. (1-Chloro-1-alkenyl)dialkylboranes gave (Z)-1-chloro-1,2-dialkylethyienes regardless of the reaction conditions. (1-Iodo-1-alkenyl)dialkylboranes failed to give satisfactory yields of 1-iodo-1,2-dialkylethylenes.

The reactions of trialkylboranes with ferric chloride and thiocyanate in an aqueous tetrahydrofuran solution give the corresponding alkyl chlorides and thiocyanates in good yields. It was found that two equivalents of ferric salts per alkyl group of organoborane are required, and not only the first alkyl group of trialkylborane but other alkyl groups are also used.

To synthesize internal alkenyldialkylboranes, coupling reactions were carried out by using 1-halo-l-alkenyldialkylboranes and Grignard reagents. Hydrogen peroxide oxidation and protonolysis with acetic acid of the reaction product revealed that internal (E)-alkenyldialkylborane was formed in 60–90% yield.

Oxygen-induced 1,4-addition reactions of trialkylboranes with cyclic a, ß-unsaturated carbonyl compounds were studied. Stereoselective 1,4-additions of the alkyl groups of trialkylboranes were observed in the reactions of d-carvone and l-perillaldehyde. Namely, it was shown that the alkyl group adds to d-carvone from the transside with respect to isopropenyl group to give the corresponding saturated ketones. The same type of one side attack of the alkyl group to l-perillaldehyde was also observed. The evidence seems to strongly support the hypothesis that coordination of boron atoms of trialkylboranes to carbonyl oxygens plays an important role, even in the oxygen-induced free radical chain reaction of organoboranes with a, ß-unsaturated carbonyl compounds.

3-Chloro-1-iodo-1-propyne is smoothly hydroborated with dialkylboranes, giving (Z)-(3-chloro-1-iodo-1-propenyl)dialkylboranes exclusively. Subsequent treatment of the hydroboration mixture with sodium methoxide or aqueous sodium hydroxide results in migration of two alkyl groups from the boron atom to the a-alkenyl carbon atom to provide dialkylated allylboranes, which are protonolyzed with methanol or water to produce 1,1-dialkyl-1-propenes. Oxidation of the allylboranes with alkaline hydrogen peroxide prior to protonolysis gives 1,1-dialkyl-2-propen-1-ols. Treatment of (Z)-(3-chloro-1-iodo-1-propenyl)dicyclohexylborane with Grignard reagents, followed by protonolysis with acetic acid, provides 3-alkyl-3-cyclohexyl-1-propenes in which the alkyl group is derived from Grignard reagent.