Recent advances in organocatalytic asymmetric multicomponent cascade reactions for enantioselective synthesis of spirooxindoles

Abstract

Asymmetric catalytic multicomponent cascade reactions have become indispensable tools for enantioselective construction of spirooxindoles. In recent years, a number of successful strategies have been developed for the synthesis of enantioenriched...

Asymmetric Synthesis of 3-Phenyl-2,3-dihydro-1H-pyrrolo[3,2-b]pyridine-3-carbonitriles Catalyzed by Phase-Transfer Catalyst Derived from tert-Leucine

“…For this purpose, a series of phase transfer catalysts 2e-2h were synthesized. When catalysts 2e-2h were used in the model reaction, moderate enantioselectivity of 68% to 75% and high diastereoselectivity of 98:2 to 99:1 were obtained (entries [5][6][7][8]. We continued to modulate benzyl, the ee value of the product was significantly improved to 83% when catalyst 2i containing 9-anthracenyl used as the catalyst, although the dr of the product decreases to 85:15 (Table 1, entry 9).…”

“…2 In recent years, amino acid-derived phase transfer catalysts have shown better activity and better enantioselectivity in Strecker reaction, 3 Rauhut-Currier reaction, 4 Mannich reaction, 5 and addition reaction. 6 The synthesis and application of chiral phase transfer catalysts derived from amino acids is also one of our research interests in developing chiral phase transfer catalysis. We have successfully applied amino acid derived phase transfer catalysts with multiple hydrogen bonds to asymmetric nitro Mannich reactions.…”

Regiodivergent Organocatalytic Reactions

“…The authors expected that the base DABCO would activate both Zard's reagent and the MBH carbonate and provide the secondary allylic trifluoromethyl thiolation product 11-3i (kinetic product) within 5 min. Upon extension of the reaction time to 30 min, the kinetic product (secondary) was rapidly isomerized into a thermodynamic product (11-2i, primary allylic trifluoromethyl thiolation product), as monitored by 19 F NMR.…”

“…Controlling the selectivity of the reactions is one of the popular fields of the research area in synthetic organic chemistry. Organocatalysts have made it possible to develop a large number of reactions to synthesize stereoselective [19][20][21][22][23][24][25][26][27][28][29], regioselective [30][31][32][33][34][35][36][37][38][39][40], and chemo-selective [41][42][43][44][45][46][47][48] products. Regiodivergent synthesis reactions, which enable two or more regioisomeric products to be synthesized from the same starting material, are controlled by various reaction parameters such as catalysts, additives, solvents, temperatures, ligands, and functional groups [49,50].…”

Organocatalyzed asymmetric dearomative 1,3‐dipolar cycloaddition of 2‐nitrobenzofurans and N‐2,2,2‐trifluoroethylisatin ketimines

“…Chiral hydrobenzofurans occur as a type of well‐known cores of many biologically active natural products and pharmaceuticals (Figure 1, right) 39–44 . Meanwhile, chiral spiro‐fused polyheterocyclic frameworks, particularly containing a spirocyclic pyrrolidine‐oxindole moiety, are also widely encountered in numerous natural alkaloids and synthetic compounds with important biological profiles (Figure 1, left) 45–52 . More importantly, the strategy of combinatorial pharmacophores plays a pivotal role in the library synthesis of promising lead compounds for new drug research and development.…”