Pd-catalyzed Direct C-H Founctionalization Of Aryl Azobenzenes

In this thesis, Pd-catalyzed direct C-H bond of azobenzene derivatives founctionalization, including sulfonylation, acyloxyation and oxyalkylation have been studied. The main results obtained are shown as follow: 1. Pd-catalyzed direct C-H bond sulfonylation of azobenzenes with arylsulfonylchloridesSulfonylazobenzenes are essential components in photosensitive composition, color filter, chemical indicator, pharmaceuticals, Raman spectroscopy and dye. However, the construction of such a structure remains largely unexploited. Herein, we have developed an efficient and highly regioselective protocol for Pd(II)-catalyzed direct C-H bond sulfonylation of azobenzenes with arylsulfonyl chlorides. Various sulfonylazobenzenes were obtained in up to 92% yields(Scheme 1). This method features with a simple system, one step operation, high efficiency, atomic economy, environmental friendliness and ligand, additives and base free conditions. Based on the results obtained and literatures, a possible reaction pathway was proposed and described in Scheme 2. 2. Pd-catalyzed direct C-O Bond Construction of Azoxybenzenes withCarboxylic Acids.A novel, simple and efficient protocol for the Pd-catalyzed direct ortho C-O bond construction of azoxybenzenes with carboxylic acids has been developed(Scheme 3). Various acyloxyazoxybenzenes were obtained in up to 97% yields. N-atom served as a directing group was confirmed by the single crystal X-ray diffraction analysis. This protocol features high regioselectivity, wide functional group tolerance and atomic economy. Based on the results obtained and literatures, a possible reaction pathway was proposed and described in(Scheme 4). 3. Pd-catalyzed direct C-O Bond Construction of Azoxybenzenes with AlcoholsA novel, simple and efficient protocol for the Pd-catalyzed direct ortho C-O bond construction of azoxybenzenes with alcohols has been developed(Scheme 5). Various alkoxylazoxybenzenes were obtained in up to 94% yields. This protocol features high regioselectivity, wide functional group tolerance and atomic economy. Based on the results obtained and literatures, a possible reaction pathway was proposed and described in(Scheme 6).