Unprecedented Selectivity via Electronic Substrate Recognition in the 1,4‐Addition to Cyclic Olefins Using a Chiral Disulfoxide Rhodium Catalyst

Abstract

From zero to hero? Sulfoxides are generally not considered useful ligand entities in asymmetric metal catalysis. However, a chiral disulfoxide as a chelating ligand in the rhodium-catalyzed 1,4-addition of aryl boronic acids to cyclic, alpha,beta-unsaturated ketones and esters gives impressive catalytic results, thus opening the door to future applications of this new chiral ligand class.

Comparing the Enantioselective Power of Steric and Electrostatic Effects in Transition‐Metal‐Catalyzed Asymmetric Synthesis

“…For both l-1 and l-2 the transition state A-B leading to the S product is higher in energy than that leading to the R product, which is in agreement with the experimentally observed preferential formation of the R product when l catalysts are used. [17][18] Further, the energy difference between the competing transition states pro-S and pro-R, 4.4 and 6.1 kcal mol À1 for l-1 and l-2, respectively, is quite high and at the end rather similar, which is in agreement with the similarly high enantioselectivity shown by these catalysts. [17][18] Overall, the l-1 and l-2 energetic profiles are very similar.…”

“…[17][18] Further, the energy difference between the competing transition states pro-S and pro-R, 4.4 and 6.1 kcal mol À1 for l-1 and l-2, respectively, is quite high and at the end rather similar, which is in agreement with the similarly high enantioselectivity shown by these catalysts. [17][18] Overall, the l-1 and l-2 energetic profiles are very similar. In both cases the energy barrier for the pro-R CÀC formation step is roughly 11-13 kcal mol À1 below the starting coordination intermediate A, the barrier for the proton transfer step (the NPA charge on the transferred H atom in transition state D-E is + 0.50e and + 0.42e for l-1 and l-2, respectively, which indicates this as a proton transfer step) is roughly 5 kcal mol…”

Synthesis, Structure, and Catalytic Studies of Palladium and Platinum Bis-Sulfoxide Complexes

“…[15][16][17][18][19][20] Successful examples where the only chelating moieties are sulfoxides are still sporadic. [21][22][23][24][25][26][27][28] Complexes of bissulfoxide ligands with palladium and platinum are known, 22,[29][30][31][32][33][34] but there are not many reports of them being used successfully in catalysis. The only examples reported are from the groups of Shibasaki 22 and White, 33 using palladium bissulfoxides.…”

Chiral N-aryl tert-butanesulfinamide-olefin ligands for rhodium-catalyzed asymmetric 1,4-addition of aryl boronic acids to cyclic enones

“…[1][2][3] In 1976, James, McMillan and Reimer reported the first asymmetric catalytic reaction with chiral sulfoxides as chiral ligands, namely ruthenium catalyzed asymmetric hydrogenation. 7 In 2009 the bis-sulfoxide ligands reported by Dorta group [8][9] and Liao group 10 accelerate the development of chiral sulfoxide ligands. Not only sulfoxides are used as ligands and catalysts, sulfinamide derivatives are developed as chiral ligands pioneered by Ellman in 2001.…”