The Research Of One-pot Synthesis Of Dibenzopyranones Via Decarboxylation And Amination Of Alcohols With Tertiary Amines

With the rapid development of society, how to protect environment and realizingsustainable development has become an unavoidable problem. All these show severechallenges to chemical researchers. Therefore, the concept “green chemistry” was putforward in the early1990s, that is how to reduce or even eliminate pollution.According to the environment friendly development need, combined with the researchof our group, this paper did some exploration about construction of C-C and C-Nbond. Herein, we reported the research of one-pot synthesis of dibenzopyranones viadecarboxylation and amination of alcohols with tertiary amines. Some detailedresearch was described as follows:We reported a Pd/Cu-based catalyst systems for dibenzopyranones synthesisreactions. Dibenzopyranone motifs are present in many natural products and biolo-gically active molecules. Traditional lactone synthesis mainly relies on Suzuki-Miyaura reaction from the corresponding boronic acids and aromatic halides.However, these methods generally require several steps and include the purification ofthe intermediates. Also, boronic acids are relatively expensive and hard to store. Thus,we had developed a one-pot synthesis of dibenzopyranones via a decarboxylativecross-coupling and lactonization sequence based on the common and cheap rawmaterial aromatic carboxylic acids. We did the pilot studies of the mechanism of thereaction, and we believed that the reaction may undergo decarboxylative cross-coupling between carboxyl and halogenated aromatics then followed by lactonizationof ester and nitro group.Besides, we reported a ruthenium-catalyzed unsymmetric tertiary amines formationfrom direct amination of alcohols with tertiary amines. We began our investigation byusing p-methylbenzyl alcohol and tributylamine as a model. We found that rutheniumcatalyst system catalyzed efficiently, yielding unsymmetric tertiary amines in yieldsup to87%. The reaction didn’t need to add any additional reducing agent, which isdifferent from reports in the literature. The reaction can be performed with a widevariety of functionalities.