Quasi-Nature Catalysis:  Developing C−C Bond Formations Catalyzed by Late Transition Metals in Air and Water

Abstract

This Account outlines the recent efforts of developing catalysis under the ambient conditions of air and water for synthetic purposes from the author's laboratory. The discussions are focused on catalytic reactions (mostly C-C bond formations) other than oxidations via late transition metals. It includes the following aspects: (1) copper-catalyzed C-C bond formations; (2) palladiumcatalyzed C-C bond formations; (3) rhodium-catalyzed C-C bond formations; (4) ruthenium-catalyzed olefin isomerizations and C-H activations. The mechanism, limitations, and synthetic applications of these reactions are also discussed.

Catalyzed Reactions of Alkynes in Water

“…(28)]. [81,82] Later, Li and co-workers found that silver complexes, such as Cy 3 PAgCl, were also a choice of catalyst for the addition of terminal alkynes to aldehydes. [83] Interestingly, the phosphine ligand served as a remarkable chemo-switch for the reaction of aldehydes with alkynes in the presence of amines in water.…”

“…(82)]. The water soluble catalyst was reused for 8 times without any significant loss in catalytic activity.…”

Green chemistry for chemical synthesis

“…In many cases, because of hydrophobic effects, using water as a solvent not only accelerates reaction rates but also enhances reaction selectivities, even when the reactants are sparingly soluble or insoluble in the medium. Furthermore, the low solubility of oxygen gas in water, an important property in the early development of life in an anaerobic environment, can facilitate airsensitive transition-metal catalysis in open air (61). The use of water as a solvent also implies the elimination of tedious protection-deprotection processes for certain acidic-hydrogen-containing functional groups, which contributes to the overall synthetic efficiency.…”

Development of Efficient Catalytic Arylation of Aldehydes with Thioether-Imidazolinium Carbene Ligands

“…[33][34][35][36][37] Especially, the development of more efficient and sustainable catalysts that are effective in only water has been desired. [38][39][40][41][42] However, the achievement of high reaction efficiency with metal catalysts in water is not easy. To overcome the poor solubility of organic compounds and deleterious effects for metal catalysts in water, ingenious aids such as microwave heating, organic co-solvents, and surfactants are often necessary.…”

“…To overcome the poor solubility of organic compounds and deleterious effects for metal catalysts in water, ingenious aids such as microwave heating, organic co-solvents, and surfactants are often necessary. [33][34][35][36][37][38][39][40][41][42] Despite these efforts, reported examples of transition metalcatalyzed arylation of aldehydes with organoboron reagents in only water are quite scarce and have unresolved issues in reaction systems and substrate generality. 43,44) The performance of palladium/thioether-imidazolinium chloride system was examined in the phenylation of 2-naphthaldehyde 7b using water as solvent (Table 4).…”