Enantioselective Synthesis of 4-Methyl-3,4-dihydroisocoumarin via Asymmetric Hydroformylation of Styrene Derivatives

P-Stereogenic Phosphorus Ligands in Asymmetric Catalysis

Chiral phosphorus ligands play a crucial role in asymmetric catalysis for the efficient synthesis of useful optically active compounds. They are largely categorized into two classes: backbone chirality ligands and P-stereogenic phosphorus ligands. Most of the reported ligands belong to the former class. Privileged ones such as BINAP and DuPhos are frequently employed in a wide range of catalytic asymmetric transformations. In contrast, the latter class of P-stereogenic phosphorus ligands has remained a small family for many years mainly because of their synthetic difficulty. The late 1990s saw the emergence of novel P-stereogenic phosphorus ligands with their superior enantioinduction ability in Rh-catalyzed asymmetric hydrogenation reactions. Since then, numerous P-stereogenic phosphorus ligands have been synthesized and used in catalytic asymmetric reactions. This Review summarizes P-stereogenic phosphorus ligands reported thus far, including their stereochemical and electronic properties that afford high to excellent enantioselectivities. Examples of reactions that use this class of ligands are described together with their applications in the construction of key intermediates for the synthesis of optically active natural products and therapeutic agents. The literature covered dates back to 1968 up until December 2023, centering on studies published in the late 1990s and later years.

Asymmetric Ruthenium-Catalyzed C-H Activation by a Versatile Chiral-Amide-Directing Strategy

A versatile and readily available chiral amide directing group has been developed for the ruthenium(II)-catalyzed asymmetric C-H activation. Asymmetric C-H activation of the related chiral benzamides with various olefins, aldehydes and propargylic alcohols has been accomplished with high stereoselectivities, affording a series of chiral products including 3,4-dihydroisocoumarins (up to 96 % ee), isocoumarins (up to 92 % ee), phthalides (up to 99 % ee), chiral bicyclo[2.2.1]heptanes (>20 : 1 dr), 4-alkylidene-3,4-dihydroisocoumarins (up to 97 % ee) and allenes (>20 : 1 dr). Importantly, our methodologies enabled concise syntheses of many biologically active compounds and natural products (e.g., Montroumarin, Cyclosporone E, Cyclosporone Q, Concentricolide, Chuangxinol, and Eleutherol).

Highly Active Rh Catalysts with Strong π-Acceptor Phosphine-Containing Porous Organic Polymers for Alkene Hydroformylation

Phosphine-containing porous organic polymers (phosphine-POPs) are a kind of potential catalyst support for alkene hydroformylation. However, the synthesis of phosphine-POPs with strong π-acceptor is still a challenge. Herein, we report the synthesis of phosphine-POPs with different π-acceptor properties [POL-P(Pyr)₃, CPOL-BPa&PPh₃-15, and CPOL-BP&PPh₃-15] and evaluated their performances as ligands to coordinate with Rh(acac)(CO)₂ for hydroformylation of alkenes. We found that the Rh center with stronger π-acceptor phosphine-POPs showed better catalytic performance. Rh/CPOL-BPa&PPh₃-15 with strong π-acceptor bidentate phosphoramidites showed obviously higher activity and regioselectivity (TON = 7.5 × 10³, l/b = 26.1) than Rh/CPOL-BP&PPh₃-15 (TON = 5.3 × 10³, l/b = 5.0) with weaker π-acceptor bidentate phosphonites. Particularly, the TON of the hydroformylation reached 27.7 × 10³ upon using Rh/POL-P(Pyr)₃ which possessed tris(1-pyrrolyl)phosphane coordination sites. Overall, our study provides an orientation to design phosphine-POPs for hydroformylation reactions.

Recent advances in Cu-catalyzed carbonylation with CO

Transition metal-catalyzed carbonylation has emerged as a powerful and versatile strategy for the efficient construction of complicated carbonyl-containing molecules from simple chemical feedstocks in the past decades.

Recent developments in asymmetric hydroformylation

This review describes the recent developments in the field of asymmetric hydroformylation. A large variety of ligands is now available, some of which are extremely effective in inducing high enantio- and regioselectivity.

Copper-Catalyzed Asymmetric Hydroamination of Styrenes with piv ZPhos as Ligand

A copper-catalyzed hydroamination of styrenes using piv ZPhos as ligand is reported. Enantioselectivities up to 94% are achieved under optimized conditions with aryl and heteroaryl styrenes. A variety of electrophilic O-benzoylhydroxylamines are well tolerated.