Rhodium catalysis arylboronic acids

Trost reported the synthesis of 1,4-dienes with ruthenium catalysis through regioselective carbometallation of alkynes with alkenes.51 Di- and trisubstituted olefins can also be obtained with arylboronic acids through an intermolecular process under rhodium,30 52 55 nickel,56 and palladium catalysis.57 Recently, Larock has reported an efficient palladium-catalyzed route for the preparation of tetrasubstituted olefins.58,59... 

The rhodium-catalyzed addition of arylboronic acids to a, 3-unsaturated ketones was first reported by Miyaura in 1997 [44], and only a short time thereafter the first enantioselective addition was documented by Hayashi [45]. Excellent reviews are available that summarize the early developments in this rapidly expanding field of asymmetric catalysis [46] consequently, only recent advances wiU be included in this section. 

Both, Hayashi and Carreira developed, independently, chiral dienes as novel ligands in asymmetric catalysis (Figure 8.6) [66]. Early investigations by Miyaura revealed that the rhodium-catalyzed conjugate addition of arylboronic acids to a,P-unsaturated ketones could be very efficiently catalyzed by a rhodium(I) complex of cyclooctadiene [67]. As a consequence, the development of chiral cod-analogues... 

Axially chiral N-arylsuccinimides were prepared by the addition of arylboronic acids to l-(2-tert-butylphenyl)maleimide (103) (Scheme 8.25), and excellent diastereo- and enantioselectivities were obtained upon catalysis with the rhodium complex of diene 51 [90]. 

Enantioselective arylation of ketimines has been carried out using rhodium catalysis with chiral sulfur-olefin ligands arylboronic acids are added in up to 99/99% yield/cc. 0... 

Complex preparation Tandem catalysis access to ketones from aldehydes and arylboronic acids via rhodium-catalyzed addition/oxidation, (52%) [1628]. 

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