Rhodium-Catalyzed Asymmetric 1,4-Addition and Its Related Asymmetric Reactions

A second-generation ligand for the enantioselective rhodium-catalyzed addition of arylboronic acids to alkenylazaarenes

“…[2][3][4] In this context, we have reported 1b the enantioselective rhodium-catalyzed 1,4-arylation [5][6][7][8] of β-substituted alkenylazaarenes with arylboronic acids using a secondary amide-containing chiral diene 9-11 ligand L1 (see Table 1, entry 1), which builds upon early studies by the groups of Lautens 12a and Genet 12b using vinylazaarenes. Although L1 was highly effective, it was of interest to determine whether a ligand of this complexity, possessing stereochemical elements additional to those of the chiral diene component, was actually necessary for optimal results.…”

Asymmetric Construction of Quaternary Carbon Stereocenter by Pd-Catalyzed Intramolecular .ALPHA.-Arylation

“…[1][2][3][4][5][6] We have been quite recently developing a novel N-heterocyclic carbene ligand 7,8) 1 based on the concept of chiral mimetic. [7][8][9][10][11][12][13] The N-heterocyclic carbene ligand 1 has been found to construct quaternary carbon streocenters with up to 65% enantioselectivity in Pd-catalyzed enantioselective intramolecular a-arylation of N-(2-bromophenyl)-N-methyl-2-arylpropanamide 2 (Chart 1).…”

Palladium(II)-catalyzed 1,4-addition of arylboronic acids to β-arylenals for enantioselective syntheses of 3,3-diarylalkanals: a short synthesis of (+)-(R)-CDP 840

“…1). The presence of either HBF 4 or AgSbF 6 (10 mol%) or both of additives was found to be effective for achieving high yields. The protocol was applied to the first catalytic synthesis of (+)-(R)-CDP 840.…”

“…The protocol was applied to the first catalytic synthesis of (+)-(R)-CDP 840. For convenience of analyses, all enantioselectivities were determined by alcohol derivatives (5) obtained by treatment of 4 with NaBH 4 since diarylaldehydes (4) were not easily separable by chiral stationary columns. Reaction between p-tolylboronic acid and trans-cinnamaldehyde was carried out at room temperature for 20 h in the presence of [Pd(S,S-chiraphos)(PhCN) 2 ](SbF 6 ) 2 (3a, 0.5 mol%) in acetone/water (10/1) to optimize the reaction conditions (Table 1).…”