Dienes haloboration

A series of books 7) and reviews 8) written on the utility of these reactions highlights the synthetic applicability of this field. However, there was no attempt to systematize the otherwise vast literature available for selective hydroboration, e.g., hydroboration of double bond in the presence of triple bond and vice versa, hydroboration of one of the double bonds of dienes, monohydroboration of alkynes, and selective hydroboration of carbon-carbon multiple bonds in the presence of many other functional groups. These topics are the aim of this review. Included here also is a brief account of the developing field of haloboration. 

Hyuga, S., Takinami, S., Hara, S., Suzuki, A. 1986. Organic synthesis using haloboration reaction. Part 9. A direct and selective synthesis of ( Z)-l-bromo-l,3-dienes and ( ,Z)-1,3-dienes by the hydrobora-tion-bromoboration sequence of two alkynes. Tetrahedron Lett. 27 977-980. 

Recently, we explored haloboration polymerization between boron tribromide and terminal diynes to give poly(organoboron halide)s as a polymeric Lewis acid, which has scarcely ever been known [13]. These poly(organoboron halide)s were also prepared by means of hydro-boration polymerization between dienes and monobromoborane as shown in Scheme 4 [14]. As a typical example, 1,7-octadiene was added to a 1.0 M dichloromethane solution of monobromoborane-dimethyl sulfide complex with stirring at 0°C under nitrogen. The molecular weight of the polymer obtained was increased when the feed ratio of monobromoborane to diene approached or slightly exceeded unity. 

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