Alkeneboronic acids

The stereodefined alkenyl halides are of prime importance due to the recent developments of di- or trisubstituted alkene synthesis by cross-coupling reactions between organometallics and alkenyl halides catalyzed by transition metal compounds 171). These alkenyl halides can be conveniently obtained from alkenylboranes or alkeneboronic acids. B-Alk enylcatecholboranes undergo rapid hydrolysis when stirred with excess water at 25 °C (Eq. 109)102). The alkeneboronic acids are usually crystalline solids of low solubility in water and can be easily isolated and handled in air without significant deterioration. 

Allylamines. Alkeneboronic acids are converted to allylamines of defined configuration on treatment with conventional Mannich reaction components (R2NH, paraformaldehyde). The required vinylboronic acids are available from 1-alkynes by reaction with catecholborane followed by hydrolysis. 

Alkaneboronic acids, 34 Alkanesulfonyl fluorides, 284 Alkeneboronic acids, 34... 

Organolead compounds sometimes act as electrophiles. Thus, ary Heads having acetoxy ligands coupled with organostannane nucleophiles with a palladium catalyst (Scheme 49). ° The same strategy was applied also to the coupling with arene- and alkeneboronic acid esters (Scheme 50). 

An alternative approach to alkeneboronic acid derivatives involves the reaction depicted in Scheme 17. ... 

Alkeneboronic esters and acids are also readily available, as in the addition of vinyl-magnesium chloride" to trimethyl borate below —50°C, followed by hydrolysis." ... 

Alkaneboronic acids, 25 Alkane diazotates, 528 Alkeneboronic adds, 70... 

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