Olefination And Addition Reaction Of Imines

We examined some facile prepared Schiff base imines and cyclic imines to a-(Benzothiazol-2-ylsulfonyl) carbonyl compounds under heat condition, products of diverse structures were obtained from different imines. We have developed asymmetric Strecker reaction of cyclic imines by using cinchonine-derived thioureas.The basic and nucleophilic zwitterions, generated by the Michael-type addition of phosphines to electron-deficient alkenes. We have pursued some reactions based on the zwitterions promoted phosphorus salts to ylide and thiazolium salt to carbene.The olefination reaction of aromatic imines with a-(benzothiazol-2-ylsulfonyl) carbonyl compounds proceeds smoothly in tetrahydrofuran at70℃to give structurally diverse α,β-unsaturated esters, amides, and ketones in good to excellent yields and with extremely high E selectivity. In contrast, the carbon-nitrogen double bonds of cyclic imines and the carbon-carbon double bonds of α,β-unsaturated imines are subjected to regiospecific vicinal difunctionalization with a-(benzothiazol-2-ylsulfonyl) carbonyl compounds under the same reaction conditions to give a variety of benzothiazole derivatives in good to excellent yields. It is noteworthy that the benzothiazole moiety is present in a number of antitumor agents and bioluminescent molecules. ESI-MS (positive mode) spectroscopic analysis of the reaction mixture, reaction intermediate have captured then we proposed reaction pathways, which proposed to proceed successively through the Mannich addition, the Smiles rearrangement, proton transfer, and the extrusion of sulfur dioxide.Study catalytic asymmetric strecker reaction of3H-indoles and2H-benzo[b][1,4]thiazines by using bifunctional cinchona alkaloids. Both quinine and quinidine based thiourea were yielded a-amino nitriles with good to excellent yields and with excellent enanatioselectivity. We have employed less toxic ethyl cyanoformate as cyanide sources and stoicheiometry of MeOH as additive in the reaction. We believe that HCN should be the actual cyanating agent.Carbon-phosphorus ylides obtained from phosphorus salts with triphenylphosphine and acrylamide, then [3+2] annulation of electron-deficient allenes produce tetrasubstitued cyclopentene. The structure was confirmed by single crystal X-ray diffractometer. By ESI-MS (positive mode) spectroscopic analysis of the reaction mixture, reaction intermediate have captured and then we proposed reaction pathways.Carbenes come from thiazolium salt with triphenylphosphine and methyl acrylate.Which catalysis benzoin condensations and Stetter reaction of aldehyde with α,β-unsaturated carbonyl compound. We also have developed a one pot series of aldehyde, a-halo carbonyl compound and secondary aldehyde successively through olefination and Stetter reaction. In this process, zwitterions which might serve as an organic base to deprotonate phosphonium salt formed by the nucleophilic attack of the phosphine to a-halo carbonyl compound. The resulting phosphine ylide react with aldehyde to give alkene. Next, carbenes which were formed by excess of zwitterions catalysis the Stetter reaction.