Studies On Oxidation And Conversion Reaction Of Alcohols Or Cyclohexanones And C-S Bond Formation From Sodium Sulfinates

In the21st century, the sustainable development of economy and society proposes new and higher requirements for chemistry, especially for synthetic organic chemistry which produces new substance. Catalyst plays a key role in modern organic reactions, the discovery and development of many well-known name reactions were based on the new catalysts and catalytic system. Therefore, the discovery new catalytic system to realize the high effective and selectivity organic synthesis transformation is a very hot and challenging topic in organic chemistry. We have been always in the development of “new methods for environmental friendly C-C bond and C-hetero bond generation reaction” as the core theme in this paper, and studies on oxidation and conversion reaction of alcohols or cyclohexanones and C-S bond formation from sodium sulfinates, respectively. The detailed research was described as follows:1. We developed a novel palladium catalyzed acylation of2-arylpyridine with primary alcohols. The cheap and stable primary alcohols were oxidized in situ to aldehydes and used as acylation reagents. Aryl ketones were obtained from pyridyl-oriented C-H bond with acyl C-H bond through a cross-dehydrogenative coupling. From a synthetic point of view, the direct introduction of carbonyl functional groups onto the aromatic motifs via C-H bond cleavage colud both be a more environmentally friendly alternative in aryl ketone synthesis and potentially provide a regioselectivity complementary to classical Friedel-Crafts acylation.2. A series of benzamides were synthesized from alcohols with nitroarenes. Hydrogen generated from alcohol oxidation in the presence of TBP acted as the nitro reducing reagent, the reaction tolerated a wide range of functionalities, and various aromatic amides were obtained in moderate to good yields in the absence of transition-metal catalyst. The nitro reduction, alcohol oxidation, and amide formation were realized in one pot.3. A series of carbazoles were synthesized from arylhydrazine hydrochlorides and cyclohexanones. Unlike the widely used Fischer–Borsche reaction, this method could be achieved in one-pot in the absence of a metal-catalyst. Molecular oxygen was used as an efficient oxidant. Temperature and solvent play important roles in the reaction. Functional groups such as methyl, ethyl, methoxy, and ester were well tolerated under the optimized conditions. 4. A series of3-arylthioindoles were synthesized from free indoles with sodium sulfinates. Disulfides were obtained when the reaction was carried out in presence of diethyl phosphate, then an iodine-catalyzed regioselective sulfenylation of free indoles with disulfides afforded3-arylthioindoles. The reaction tolerated a wide range of functionalities, and various3-arylthioindoles were obtained in moderate to good yields in the absence of transition-metal catalyst.5. Iodine-catalyzed selective2-arylsulfonyl indole formation from indoles and sodium sulfinates is disclosed. A catalytic amount of iodine and one equivalent of TBHP acted as efficient promoter for this transformation, and the reaction could be finished in a couple of hours at room temperature in the absence of transition-metal catalyst. The direct sulfonylation reaction occurred exclusively at the C-2position of the indole ring. Many functional groups were well tolerated.