Chiral Diene Ligands in Asymmetric Catalysis

Abstract

Asymmetric catalysis has emerged as a general and powerful approach for constructing chiral compounds in an enantioselective manner. Hence, developing novel chiral ligands and catalysts that can effectively induce asymmetry in reactions is crucial in modern chemical synthesis. Among such chiral ligands and catalysts, chiral dienes and their metal complexes have received increased attention, and a great progress has been made over the past two decades. This review provides comprehensive and critical information on the essential aspects of chiral diene ligands and their importance in asymmetric catalysis. The literature covered ranges from August 2003 (when the first effective chiral diene ligand for asymmetric catalysis was reported) to October 2021. This review is divided into two parts. In the first part, the chiral diene ligands are categorized according to their structures, and their preparation methods are summarized. In the second part, their applications in asymmetric transformations are presented according to the reaction types.

Chiroptical Elastomer Film Constructed by Chiral Helical Substituted Polyacetylene and Polydimethylsiloxane: Multiple Stimuli Responsivity and Chiral Amplification

“…The monomers and polymers were identified by FT-IR (Bruker Tensor II) and 1 H NMR (Bruker AV600). The number-average molecular weight (M n ) and polydispersity index (PDI, M w /M n ) of polymers were determined by GPC (Waters 515-2410).…”

“…The most distinctive manifestation of chirality in chemistry is the optical activity of chiral structures, expressed as optical rotation or circular dichroism (CD). Chiral materials have demonstrated broad application prospects, such as in asymmetric catalysis, chiral sensing, chiral separation, and so on. − On the other hand, chirality can be divided into configurational chirality, conformational chirality, and phase chirality at molecular scales . As far as chiral polymers are concerned, the relevant research has mainly focused on conformation chirality and phase chirality.…”

Rhodium-Catalyzed Highly Enantio- and Diastereoselective Alkenylation of β,γ-Unsaturated Butenolides via Dynamic Kinetic Resolution

“…Experimental details and characterization data, including 1 H and 13 C NMR spectra, HPLC charts, and X-ray data (PDF)…”

“…Subsequently, a commercially available chiral diene ligand, (S,S)-Ph-bod (L3), 12 was tested under the conditions and smoothly gave 3aa in 84% yield with 99% ee and 6:1 dr (entry 4). To further improve the diastereoselectivity, a series of chiral diene ligands 13 were screened (entries 5−10). Comparatively, the ester-containing chiral diene ligands L4−L6 resulted in a decrease in yield and ee while the amide-containing one (L7) showed competitive reactivity (80% yield) and selectivity (98% ee, 7:1 dr).…”

Rhodium-Catalyzed Asymmetric 1,4-Addition of α/β-(N-Indolyl) Acrylates

“…Rhodium-catalyzed asymmetric 1,4-addition of organoboron reagents to electron-deficient olefins has been realized as one of the most powerful strategies for the construction of a chiral stereocenter . In recent years, our group has developed a series of novel chiral olefin ligands for asymmetric catalysis, including chiral sulfur-olefins, phosphorus-olefins, and C 1 / C 2 -chiral dienes . With these elegant olefin ligands, asymmetric 1,4-addition over a broad range of α,β -unsaturated substrates can be achieved under rhodium catalysis with high enantioselectivity .…”