Our recent studies on asymmetric propargylic substitution reactions by using transition metal catalysts and organocatalysts are reviewed from the viewpoint of organic synthesis. Ruthenium and copper complexes bearing optically active ligands work as effective catalysts toward propargylic alkylation, paropargylic amination, propargylic etherification, propargylation of aromatic compounds, and related reactions to give the corresponding propargylic substituted products with a high enantioselectivity. Cooperative reactions by using both transition metal catalysts and organocatalysts are also described.

Previously, organocopper reagents that were compatible with allylic substitution of secondary allylic esters were limited in most cases to alkyl reagents, whereas arylcopper species have often resulted in poor results due to less nucleophilic property than that of alkylcopper species. To find a reactive class of allylic esters and arylcopper reagents, we selected allylic picolinates of a (Z)-R¹CH=CHCH(OCOPy)R² structure, which reacted with arylcopper reagents derived from ArMgBr and CuBr·Me₂S, furnishing anti S_N2’ products in good yields with high regio- and stereoselectivity. Next, allylic substitution was extended successfully to organolithium-based arylcopper reagents. Furthermore, we established allylic substitution with heteroaryl and alkynyl reagents, which are in general less nucleophilic than aryl reagents. Furthermore, allylic substitutions of R¹R²C=CHCH(OCOPy)R³ and cyclohexylidene picolinates furnished corresponding quaternary carbons. The stereochemical outcome in the latter case was explained by a stable chair conformer and the equatorial attack of the reagent to the conformer. Synthetic applications using allylic substitution are described as well.

π-Allylpalladium is usually recognized to serve as synthetically useful electrophilic allylating agents toward many nucleophiles. On the other hand, σ-allylpalladium possessing ligands that donate electrons acts as nucleophilic allylating agents toward electrophiles. We demonstrated the distinct reactivities of allylic gem-palladium/metalloid intermediates that could serve as C3 units in reactions other than allylation reactions by σ-allylpalladium. (1) Palladium-catalyzed highly stereoselective cyclopropanation of strained alkenes with organometalloid-substituted 1-arylallyl acetates. (2) Self-dimerization of Pd(0)-complexed 3-aryl or 2,3-diaryl vinylcarbenes generated from organometalloid-substituted σ-allylpalladium intermediates to provide 1,6-di- or 1,2,5,6-tetra-arylhexa-1,3,5-trienes. (3) Three-component reaction of 3-(pinacolatoboryl)- or 3-(n-tributylstannyl)allyl acetates, aldehydes, and organoboranes to afford the (Z)- or (E)-anti-homoallylic alcohols with excellent diastereoselectivity and good to high levels of alkene stereocontrol.

Palladium-catalyzed cyclization of propargylic esters with bis-nucleophiles is one of the useful method for the construction of cyclic molecules in one step. A variety of products could be synthesized in one step by the choice of adequately designed nucleophilic molecules. In this review, we describe a comprehensive overview of our studies on palladium-catalyzed reactions of propargylic esters with bis-nucleophiles. The reactions afforded various functionalized hetero- and carbocyclic molecules in a regio- and stereoselective manner.

Self-assembly has been utilized for the spontaneous formation of nanoarchitectures. Therein, a small change in the molecular structure dramatically alters the resulting macroscopic self-assembly morphologies and the consequent material properties. This macroscopic expression of the small initial difference via self-assembly can be alternatively regarded as precise translation of molecular structural information. In this contribution, we offer a novel molecular recognition concept utilizing self-assembly phenomena. A small difference in guest structures affords distinctly different self-assembly modes of fluorescent (FL) chemosensors, leading to their sensory responses characteristic to the guest structures. Thus, self-assembly has now been utilized as a FL sensory system for molecular recognition, particularly, of biologically important molecules and polymers. Here, we demonstrate that the integral magnitude of binding mechanism, self-assembly, and FL response realizes (i) selective FL detection of ATP, (ii) FL differentiation of dicarboxylates and keto-acids, and (iii) unexpectedly selective FL sensing of hyaluronic acid among glycosaminoglycans.

Carbonyl-olefin metathesis reaction is an attractive method to construct new carbon-carbon double bonds from carbonyl compounds and olefins. Nevertheless, a limited number of carbonyl-olefin metathesis has been reported. In addition, they required photoirradiation or stoichiometric amount of activators such as transition metal complexes, Brønsted acids, and Lewis acids. Oligomerization of substrates or reverse reaction of products often occurred. Since 2012, efficient and catalytic carbonyl-olefin metathesis reactions have emerged. This review highlights recent advances about catalytic carbonyl-olefin metathesis reactions.

Arylsilanes are valuable intermediates for synthesis of various compounds, such as biaryls, by simple transformations. For synthesis of arylsilanes, direct C-H/Si-H coupling reaction is an attractive strategy from the both viewpoints of cost efficiency and environmental friendliness. This review described recent achievement of intermolecular dehydrogenative C-H silylation of undirected aromatic compounds.