| Transition metal on rhenium-catalyzed C-H activation strategies can efficiently build C-C bonds,but the oxidants are often required to add to complete the catalytic cycle in such reactions.In recent years,chemists had designed a substrate containing an oxidizing directing group.These substrates did not require additional oxidizing agents in the reaction,which simplifies the reaction system and improves the reaction efficiency.β-aryl ketone compounds are widely found in natural products,such as chalcone compounds.These compounds have good biological activity such as antibacterial,antioxidant,anti-cancer,anti-HIV activities,and also are served as important intermediates for the synthesis of natural products.However,there are some problems as following for the synthesis ofβ-aryl ketone compounds at the present time:harsh reaction conditions,poor tolerance of functional groups,cumbersome reaction steps,low synthesis efficiency,and poor reaction selectivity.In order to explore a mild condition to constructβ-aryl ketone skeletons,Rh（III）-catalyzed C-H activation strategy was used through N-phenoxyacetamide and allyl alcohols.For the selective synthesis ofβ-aryl ketones and unsaturatedβ-aryl ketones,we have done the following research:1.The reaction conditions for the synthesis ofβ-aryl ketones using N-phenoxyacetamide as a substrate were explored.Through the screening of temperature,additives,solvents,and catalysts,we found the thatβ-aryl ketone product is obtained by one-step reaction in methanol solution at60°C using[Cp*RhCl2]2 as the catalyst,and Zn（OAc）2 as the additive.With the optimal conditions established,the scope and limitations of this system were then examined,and the yield is in the range from 61%to 92%.2.The reaction conditions for the synthesis of unsaturatedβ-aryl ketones using N-phenoxyacetamide as a substrate were explored.The unsaturatedβ-aryl ketone was obtained in a one-step reaction at room temperature using[Cp*Rh（MeCN）3][SbF6]2 as the catalyst,tert-butanol as solution and CsF as the additive.After the reaction scope,the yield is in the range from50%to 71%.3.Through KIE parallel experiments,the reaction mechanism ofβ-aryl ketone formation was speculated.4.We used the synthetic substrate 2-hydroxydihydrochalcon for derivative studies to obtain two classes of compounds with a lignan skeleton and a proscarinoid skeleton;and this method is used for the alkyl ketoneification modification in the O-hydroxy position of estrone.The method of construction ofβ-aryl ketones and unsaturatedβ-aryl ketones in one step using Cp*Rh（III）as catalyst,N-phenoxyacetamide as a substrate was explored in this paper.The reaction conditions were mild,had high selectivity and strong functional group tolerance.As no external oxidant was used,the atomic utilization was increased which was consistent with the concept of green chemistry.The method has reference value for the total synthesis and structural modification of natural products. |
