https://pubs.rsc.org/en/content/articlepdf/2019/NP/C8NP00092A

Marine natural products.

Pick your Pd partners: A number of catalytic systems have been developed for palladium-catalyzed CH activation/CC bond formation. Recent studies concerning the palladium(II)-catalyzed coupling of CH bonds with organometallic reagents through a PdII/Pd0 catalytic cycle are discussed (see scheme), and the versatility and practicality of this new mode of catalysis are presented. Unaddressed questions and the potential for development in the field are also addressed.

In the past decade, palladium-catalyzed CH activation/CC bond-forming reactions have emerged as promising new catalytic transformations; however, development in this field is still at an early stage compared to the state of the art in cross-coupling reactions using aryl and alkyl halides. This Review begins with a brief introduction of four extensively investigated modes of catalysis for forming CC bonds from CH bonds: PdII/Pd0, PdII/PdIV, Pd0/PdII/PdIV, and Pd0/PdII catalysis. A more detailed discussion is then directed towards the recent development of palladium(II)-catalyzed coupling of CH bonds with organometallic reagents through a PdII/Pd0 catalytic cycle. Despite the progress made to date, improving the versatility and practicality of this new reaction remains a tremendous challenge.

/pdf/palladium-ii-catalyzed-c-h-activation-c-c-cross-coupling-2546yox1wp.pdf

Palladium(II)-catalyzed C-H activation/C-C cross-coupling reactions: versatility and practicality.

s, or keywords if they used Heck-type chemistry in their syntheses, because it became one of basic tools of organic preparations, a natural way to

http://aether.cmi.ua.ac.be/artikels/Artikels%20Gitte/Artikels/Reviews/Heck%20reactie%20Beletskaya%20%20Chem.%20Rev.%20003009.pdf

The heck reaction as a sharpening stone of palladium catalysis.

https://www.erowid.org/archive/rhodium/pdf/suzuki.cross-coupling.review.1995-1998.pdf

Recent advances in the cross-coupling reactions of organoboron derivatives with organic electrophiles, 1995–1998

Molecular self-assembly is the spontaneous association of molecules under equilibrium conditions into stable, structurally well-defined aggregates joined by noncovalent bonds. Molecular self-assembly is ubiquitous in biological systems and underlies the formation of a wide variety of complex biological structures. Understanding self-assembly and the associated noncovalent interactions that connect complementary interacting molecular surfaces in biological aggregates is a central concern in structural biochemistry. Self-assembly is also emerging as a new strategy in chemical synthesis, with the potential of generating nonbiological structures with dimensions of 1 to 10(2) nanometers (with molecular weights of 10(4) to 10(10) daltons). Structures in the upper part of this range of sizes are presently inaccessible through chemical synthesis, and the ability to prepare them would open a route to structures comparable in size (and perhaps complementary in function) to those that can be prepared by microlithography and other techniques of microfabrication.

Molecular self-assembly and nanochemistry: A chemical strategy for the synthesis of nanostructures

Lanthanide complexes in multifunctional asymmetric catalysis.

This review focuses on a new concept in catalytic asymmetric reactions that was first realized for the use of heterobimetallic complexes. As these heterobimetallic complexes function as both a Bronsted base and as a Lewis acid, just like an enzyme, they make possible a variety of efficient catalytic asymmetric reactions. This heterobimetallic concept should prove to be applicable to a variety of new asymmetric catalyses. The first part of this review describes the development of rare-earth–alkali metal complexes such as LnM3tris(binaphthoxide) complexes (LnMB, Ln = rare-earth metal, M = alkali metal), which are readily prepared from the corresponding rare-earth trichlorides or rare-earth isopropoxides, and their application to catalytic asymmetric synthesis. By using a catalytic amount of LnMB complexes several asymmetric reactions proceed efficiently to give the corresponding desired products in up to 98% ee: LnLB-catalyzed asymmetric nitroaldol reactions (L = Li), LnSB-catalyzed asymmetric Michael reactions (S Na), and LnPB-catalyzed asymmetric hydrophosphonylations of either imines or aldehydes (P K). Applications of these heterobimetallic catalysts to the syntheses of several biologically and medicinally important compounds are also described. Spectral analyses and computational simulations of the asymmetric reactions catalyzed by the heterobimetallic complexes reveal that the two different metals play different roles to enhance the reactivity of both reaction partners and to position them. From mechanistic considerations, a useful activation of the heterobimetallic catalyses was realized by addition of alkali metal reagents. The second part describes the development of another type of heterobimetallic catalysts featuring Group 13 elements such as Al and Ga as the central metal. Among them, the AlLibis(binaphthoxide) complex (ALB) is an effective catalyst for asymmetric Michael reactions, tandem Michael–aldol reactions, and hydrophosphonylation of aldehydes.

Asymmetric Catalysis with Heterobimetallic Compounds

The concept of bifunctional catalysis, wherein both partners of a bimolecular reaction are simultaneously activated, is very powerful for designing efficient asymmetric catalysts. Catalytic asymmetric processes are indispensable for producing enantiomerically enriched compounds in modern organic synthesis, providing more economical and environmentally benign results than methods requiring stoichiometric amounts of chiral reagents. Extensive efforts in this field have produced many asymmetric catalysts, and now a number of reactions can be rendered asymmetric. We have focused on the development of asymmetric catalysts that exhibit high activity, selectivity, and broad substrate generality under mild reaction conditions. Asymmetric catalysts based on the concept of bifunctional catalysis have emerged as a particularly effective class, enabling simultaneous activation of multiple reaction components. Compared with conventional catalysts, bifunctional catalysts generally exhibit enhanced catalytic activity and higher levels of stereodifferentiation under milder reaction conditions, attracting much attention as next-generation catalysts for prospective practical applications. In this Account, we describe recent advances in enantioselective catalysis with bifunctional catalysts. Since our identification of heterobimetallic rare earth-alkali metal-BINOL (REMB) complexes, we have developed various types of bifunctional multimetallic catalysts. The REMB catalytic system is effective for catalytic asymmetric Corey-Chaykovsky epoxidation and cyclopropanation. A dinucleating Schiff base has emerged as a suitable multidentate ligand for bimetallic catalysts, promoting catalytic syn-selective nitro-Mannich, anti-selective nitroaldol, and Mannich-type reactions. The sugar-based ligand GluCAPO provides a suitable platform for polymetallic catalysts; structural elucidation revealed that their higher order polymetallic structures are a determining factor for their function in the catalytic asymmetric Strecker reaction. Rational design identified a related ligand, FujiCAPO, which exhibits superior performance in catalytic asymmetric conjugate addition of cyanide to enones and a catalytic asymmetric Diels-Alder-type reaction. The combination of an amide-based ligand with a rare earth metal constitutes a unique catalytic system: the ligand-metal association is in equilibrium because of structural flexibility. These catalytic systems are effective for asymmetric amination of highly coordinative substrate as well as for Mannich-type reaction of alpha-cyanoketones, in which hydrogen bonding cooperatively contributes to substrate activation and stereodifferentiation. Most of the reactions described here generate stereogenic tetrasubstituted carbons or quaternary carbons, noteworthy accomplishments even with modern synthetic methods. Several reactions have been incorporated into the asymmetric synthesis of therapeutics (or their candidate molecules) such as Tamiflu, AS-3201 (ranirestat), GRL-06579A, and ritodrine, illustrating the usefulness of bifunctional asymmetric catalysis.

Recent progress in asymmetric bifunctional catalysis using multimetallic systems.

The direct catalytic asymmetric aldol reaction using aldehydes and unmodified ketones is described for the first time herein. This reaction was first found to be promoted by 20 mol % of anhydrous (R)-LLB (L = lanthanum, L = lithium, B = (R)-binaphthol moiety) at −20 °C, giving a variety of aldol products in ee's ranging from 44 to 94%. This asymmetric reaction has been greatly improved by developing a new heteropolymetallic asymmetric catalyst [(R)-LLB, KOH, and H2O]. Using 3−8 mol % of this catalyst, a variety of direct catalytic asymmetric aldol reactions were again found to proceed smoothly, affording aldol products in ee's ranging from 30 to 93% and in good to excellent yields. Interestingly, the use of this new heteropolymetallic asymmetric catalyst has realized a diastereoselective and enantioselective aldol reaction using cyclopentanone for the first time. It is also noteworthy that a variety of aldehydes, including hexanal, can be utilized for the current direct catalytic asymmetric aldol reaction...

Masakatsu Shibasaki

Papers

Lanthanide complexes in multifunctional asymmetric catalysis.

Asymmetric Catalysis with Heterobimetallic Compounds

Recent progress in asymmetric bifunctional catalysis using multimetallic systems.

Direct Catalytic Asymmetric Aldol Reaction

Direct Catalytic Asymmetric Aldol Reactions of Aldehydes with Unmodified Ketones