10.4.3 Vinylboranes

Borane with alkynes gives vinylboranes that serve as useful intermediates in organic synthesis. For example, 1-hexyne with catcholborane yields trans -1-alkenylborone that can be converted into trans -vinyl iodide and cis -vinyl bromide that are substrate precursors for the C-C coupling reactions using palladium catalysis (Scheme 14). Vinylboranes can also be converted into aldehydes, ketones or alkenes and the reactivity and selectivity depend on the nature of organoboranes used (Scheme 15).

 

Scheme 15

10.4.4 Suzuki Coupling

The coupling of organic boronic acid with halides or triflates using palladium-catalysis leads to a powerful protocol for the carbon-carbon bond formation (Scheme 17). The mechanism has been discussed in lecture 34.

Scheme 16

Examples: