Studies On The Catalytic α─C─H Activation And C─C Bond Formation Reactions Of Functionalized Ketene Dithioacetals

Functionalized ketene-(S,S)-acetals chemistry has become an important division in organic chemistry. Through the development of nearly one hundred years, about functionalizedα-oxo ketene-(S,S)-acetals chemistry’s synthesis methodology and applied research have become features study in organic chemistry. Especially in the past three decades, quite amount of documents have been published in this field, and several reviews reported and summarized these findings.Functionalized ketene-(S,S)-acetals are easier to prepare and bear much more functionalities. We have had the extensive studies on theα-carbamoyl ketene-(S,S)-acetals and its further applications. Becauseα-position of ketene-(S,S)-acetals have strong nucleophilic and their Baylis-Hillman reaction with aldehydes giveÎ'Ηadducts. Developments of new basic reactions and new synthetic methods are the basis for the innovation and advancement of organic chemistry. Based on the research achievement of our group inα-oxo ketene-(S,S)-acetal chemistry in the past decades, the aim of increase BH reaction efficiency and practical value, my thesis starts from the synthesis ofα-EWG ketene-(S,S)-acetals through synthetic design, aiming to develop new basic reactions and new synthetic methods for interesting cyclic molecules and consequently found a new synthetic strategy to provide a general and simple route to C-C Bond Formation. However, researches on Functionalized ketene-(S,S)-acetals catalyzed by transition metal remained poorly explored, the understanding of the forming of C-C bond atα-position is far from enough. Therefore, studies and applications of the C-C bond formation atα-position ofα-EWG ketene-(S,S)-acetals are research projects of great significance.The thesis mainly includes the following four aspects.1. Investigate the reaction of CuBr2 catalyzed ketene-(S,S)-acetals with aldehydes and a facile synthesis a rang of coumarins. The reactions have multifunctionality in the molecules, excellent yields and mild conditions.2. The Mannich reaction of ketene-(S,S)-acetals, aldehydes and amines catalyzed by CuBr2 were carried out. These compounds can be potentially useful intermediates in organic synthesis due to the multifunctionality in the molecules and highly reaction activated which also can generated pyridones.3. In the first presence of HBr, the activated arenes C─C Bond formation reaction of ketene-(S,S)-acetals and aldehydes were performed and generated the corresponding BH adducts. The above experimental results revealed that the catalytic of Hydrobromic acid involve Sulfur-oriented C-H Bond activation induce C─C Bond formation reaction.4. By the catalytic of Hydrobromic acid involve Sulfur-oriented C─H Bond activation, a serie of C─C Bond adducts were prepared. The simple procedure, mild condition, easy separation, high yield, make this protocol most attractive for the applied of usual arenes and aldehydes.