An efficient ruthenium catalyst is reported, for the first time, to catalyse the α‐methylation of ketones and esters using methanol as a green methylating agent. The in situ generated catalyst from the complexes [RuCp*Cl2]2 or [RuCp*Cl2]n with dpePhos provided up to quantitative yields in the presence of only 20 mol% of lithium tert‐butoxide (LiO‐t‐Bu) as a base. Regioselective mono‐ or multi‐methylation could be effectively controlled by temperature. This catalyst system was also effective for the one‐pot sequential α‐alkylation–α‐methylation of methyl ketones and conjugate reduction–α‐methylation of α,β‐unsaturated ketones to synthesise α‐branched ketones. An application of the α‐methylation of esters using the ruthenium catalyst was demonstrated for an alternative catalytic synthesis of Ketoprofen.
An unprecented N‐ and C(3)‐dialkylation of unactivated amines by a cascade reaction via borrowing hydrogen methodology using new (arene)ruthenium(II) complexes featuring phosphinosulfonate ligands is described. This reaction is highly regioselective and produces water as the only side product. 相似文献
We demonstrate a borrowing hydrogen methodology using the unique reactivity of the π‐benzylpalladium system in water, which offers an efficient and environmentally friendly N‐monobenzylation of electron‐deficient anilines or 2‐aminopyridine with non‐activated benzylic alcohols under neutral conditions. The crossover experiment using benzyl‐α,α‐d2 alcohol and 3‐methylbenzyl alcohol afforded H/D scrambling products, suggesting that the borrowing hydrogen pathway occurred in our catalytic system. Our simple protocol can accomplish a gram scale reaction of 2‐aminobenzonitrile (76 % isolated yield), and is performed with the use of only 1 mol % Pd(OAc)2 and 2 mol % TPPMS without other additives in water.
In this paper a new theory referred to as the decrease-radix design （DRD） is proposed, which is found in the research of logic units of ternary （tri-valued） optical computer. Based on the theory proposed, the principles and the regulations of the DRD for making operation units of multi-valued operation with carrying/borrowing free are also presented. The research work has come to the following important conclusion： let D be a special state contained in n physical informative states, then one may figure out any multi-valued processors within n^（n×n） carrying/borrowing free n-valued units by the composition some of n×n×（n-1） simplest basic operating units according to the regulations of DRD proposed in this paper. The detailed systematic way of our design regulations is highlighted step by step in the paper with an example of design of a tri-valued logic optical operating unit. The real architecture, the procedure, and the experimental results of our sample in tri-valued logic operating unit are given. Finally, a re-constructible model of ternary logical optical processor is introduced. The theory proposed in the paper has laid down a solid foundation for the design of re-constructible carrying/borrowing free operating units in ternary optical computers and can be widely used as the designing reference in a variety of multi-valued logic operating units. 相似文献
