Palladium Catalyzed Enantioselective Hayashi–Miyaura Reaction for Pharmaceutically Important 4-Aryl-3,4-dihydrocoumarins

Abstract

The first palladium-catalyzed asymmetric addition of arylboronic acids to coumarins was successfully established, providing a straightforward asymmetric approach to achieving pharmaceutically important 4-aryl-3,4-dihydrocoumarins. This methodology features easily accessible and bench-stable ligands, a wide substrate scope, mild conditions, and accommodation of electron-withdrawing arylboronic acids.

Nickel-Catalyzed Enantioselective Reductive Conjugate Arylation and Heteroarylation via an Elementary Mechanism of 1,4-Addition

“…In the past, chiral copper catalysts have dominated in asymmetric conjugate addition of arylmetal reagents, for example, Li, Mg, Al, Zn, and so on (see Figure a) . For conjugate addition of aryl-nonmetal reagents, especially air-stable arylborons, however, stereoselective examples catalyzed by copper still remain limited. , In comparison, 4d transition metals Rh and Pd have met great success in promoting conjugate addition of both organoboron reagents (Figure b). In particular, the rhodium-catalyzed Hayashi–Miyaura reaction has become the state-of-the-art in asymmetric metal catalysis in terms of excellent levels of stereocontrol and substrate diversity, for example, including both cyclic and acyclic acceptors.…”

Asymmetric Pd(II)‐Catalyzed C−O, C−N, C−C Bond Formation Using Alkenes as Substrates: Insight into Recent Enantioselective Developments

“…The protocol, involving Pd(TFA) 2 and chiral t Bu−carboline−oxazoline ligand L34 , was compatible with either electron‐withdrawing or electron‐donating groups on the arylboronic acids and on the substituted coumarins. Limitations were observed with the use of aliphatic boronic acids [131] …”

Enantioselective construction of ortho-substituted benzylic quaternary centers using a phenanthroline-Pd catalyst

“…1 The transition metal-catalyzed conjugate addition of aryl nucleophiles to suitable β,β-disubstituted enones is a useful approach to construct benzylic all-carbon quaternary centers. 2–7 Among the numerous methods, Rh- and Pd-catalyzed conjugate additions to enones with organoboron reagents have attracted attention because of the stability toward air and moisture and functional group tolerance, as well as the availability and broad scope, of the reaction. 2 g ,3–7…”

“…2–7 Among the numerous methods, Rh- and Pd-catalyzed conjugate additions to enones with organoboron reagents have attracted attention because of the stability toward air and moisture and functional group tolerance, as well as the availability and broad scope, of the reaction. 2 g ,3–7…”

“…Pd-catalyzed conjugate addition of ortho -substituted arylboronic acids to β,β-disubstituted enones often results in low yields of the corresponding ketone products because having a quaternary center vicinal to an ortho -substituted phenyl ring is a very congested situation. 2–7 We have previously reported the use of 1,10-phenanthroline fused with a chiral bicyclo[3.3.0]octane framework as a chiral ligand in the Pd-catalyzed conjugate addition of phenylboronic acid to 2-cyclohexen-1-one and chromone. The mechanism of this stereoselective conjugate addition was discussed from the perspective of the structure of the chiral phenanthroline-Pd complex obtained by single crystal X-ray crystallography.…”