Rhodium‐Catalyzed Asymmetric Conjugate Addition of Organoboronic Acids to Carbonyl‐Activated Alkenyl Azaarenes

Abstract

The enantioselective synthesis of chiral azaarenes by rhodium‐catalyzed asymmetric conjugate addition of organoboronic acids to carbonyl‐activated alkenyl azaarenes was reported. Diverse chiral azaarenes were produced in up to 99% yield and with up to 99% ee (>60 examples). Catalytic asymmetric syntheses of dexchlorpheniramine and dexbrompheniramine were realized by using the developed method.magnified image

Exploring the copper binding ability of Mets7 hCtr‐1 protein domain and His7 derivative: An insight in Michael addition catalysis

“…This reaction represents an important synthetic tool to form new C–C bonds, and it is commonly used for the obtainment of valuable synthetic intermediates. Three different benzoyl group‐activated olefins such as the 2‐ or 4‐imidazolyl enones ( 2 and 3 respectively) and the 2‐pyridinyl enone 4 were synthesized and evaluated as substrates for the synthesis of the corresponding chiral products using the obtained Mets7 and His7 complexes 13 . A preliminary screening (See Supporting Information) in which different reaction conditions were tested, changing the solvent, substrate/catalyst ratio, basic additive and temperature, was first performed.…”

“…[6][7][8][9] Indeed, despite the achievements obtained using transition metal catalysts based on chiral diphosphines and N-chelating ligands, many transformations are still hampered by several issues concerning reactivity and selectivity. [10][11][12][13][14][15][16] Conversely, enzymes often outperform transition metal catalysts with higher levels of efficiency and of chemoselectivity, regioselectivity and stereoselectivity, [17][18][19][20] giving thus an inspiration for the development of enzyme-like transition metal hybrid catalysts. [19][20][21][22][23] Combining the rational design of the peptide ligand and the choice of an appropriate metal, it is possible to merge the high reactivity of transition metals with the structural and functional groups versatility of peptides, achieving levels of reactivity otherwise unrealisable.…”

“…It is thus not surprising that chemists have been exploring the advantageous properties of peptides as ligands for metal ions for asymmetric catalysis 6–9 . Indeed, despite the achievements obtained using transition metal catalysts based on chiral diphosphines and N ‐chelating ligands, many transformations are still hampered by several issues concerning reactivity and selectivity 10–16 . Conversely, enzymes often outperform transition metal catalysts with higher levels of efficiency and of chemoselectivity, regioselectivity and stereoselectivity, 17–20 giving thus an inspiration for the development of enzyme‐like transition metal hybrid catalysts 19–23 .…”

Rate Dependence on Inductive and Resonance Effects for the Organocatalyzed Enantioselective Conjugate Addition of Alkenyl and Alkynyl Boronic Acids to β-Indolyl Enones and β-Pyrrolyl Enones

“…The use of boronate esters and boronic acids as nucleophiles in catalyzed conjugate additions to enones dates to Suzuki [ 99 , 108 , 109 , 110 , 111 , 112 ]. More recent efforts have led to transition metal-catalyzed and organocatalyzed enantioselective versions of this reaction.…”

“…This report describes why these substrates are problematic, how resonance effects impact the reaction rate and success, and how to increase these substrates' reactivity. The use of boronate esters and boronic acids as nucleophiles in catalyzed conjugate additions to enones dates to Suzuki [99,[108][109][110][111][112]. More recent efforts have led to transition metal-catalyzed and organocatalyzed enantioselective versions of this reaction.…”