Enantioselective Synthesis of β-Aryloxycarboxylic Esters via Asymmetric Hydrogenation of β-Aryloxy-α,β-Unsaturated Esters

Abstract

A novel synthesis of β-aryloxycarboxylic esters via asymmetric hydrogenation of the corresponding β-aryloxy-α,β-unsaturated esters has been demonstrated. Bis(norbornadiene)rhodium(I) tetrafluoroborate (1 mol %) and Walphos W008-1 were used to generate the saturated products with high enantioselectivity and in high yield. The tolerability of the reaction to a diverse range of substituents on the aromatic ring was also explored.

Comparison of Asymmetric Hydrogenations of Unsaturated Carboxylic Acids and Esters

“…78 In that transformation there are no obvious CFGs for Rh(1+) or other ways for the substrate to form out-of-sphere association with the ligand. The in situ generated catalyst involved in these reactions was probably identified from a broad screening effort.…”

CuO‐Catalyzed 1,3‐Addition of Diaryliodonium Triflates to Diazo Esters for the Stereoselective Synthesis of Triflate‐Substituted β‐Aryloxyl Acrylates

“…The β‐aryloxyl acrylates and analogous compounds are widely used to constitute a class of organic compounds as the main structural units or intermediates They are found to be widely useful in the synthesis of many useful biologically and pharmaceutically concentrated oxygen‐containing heterocycles, including benzofurans, flavones, and phthalans . Besides, partial dimerization of compounds itself gives 4‐aryldihydro‐coumarins as the product, which roles as significant skeletons in natural products .…”

Nickel‐Promoted Highly Regioselective Carboxylation of Aryl Ynol Ether and Its Application to the Synthesis of Chiral β‐Aryloxypropionic Acid Derivatives

“…Therefore, a variety of methodologies for the synthesis of β‐aryloxypropionic acid derivatives as an enantioenriched form have been reported 7. One straightforward and promising method for the synthesis of enantioenriched β‐aryloxypropionic acid derivatives is the asymmetric hydrogenation of the β‐aryloxyacrylate derivatives, and iridium‐8a,b and rhodium‐catalyzed8c hydrogenation reactions have recently been demonstrated.…”