%0 Generic %A Tu, Xing-Jun %A Hao, Wen-Juan %A Ye, Qin %A Wang, Shuang-Shuang %A Jiang, Bo %A Li, Guigen %A Tu, Shu-Jiang %D 2015 %T Four-Component Bicyclization Approaches to Skeletally Diverse Pyrazolo[3,4‑b]pyridine Derivatives %U https://acs.figshare.com/articles/dataset/Four_Component_Bicyclization_Approaches_to_Skeletally_Diverse_Pyrazolo_3_4_i_b_i_pyridine_Derivatives/2044260 %R 10.1021/jo502096t.s002 %2 https://acs.figshare.com/ndownloader/files/3615576 %K multicyclic %K 17 examples %K bicyclization %K 37 examples %K pyrazolo %X A novel four-component bicyclization strategy has been established, allowing a flexible and practical approach to 37 examples of multicyclic pyrazolo­[3,4-b]­pyridines from low-cost and readily accessible arylglyoxals, pyrazol-5-amines, aromatic amines, 4-hydroxy-6-methyl-2H-pyran-2-one, and cyclohexane-1,3-diones. The polysubstituted cyclopenta­[d]­pyrazolo­[3,4-b]­pyridines were stereoselectively synthesized through a microwave-assisted special [3+2+1]/[3+2] bicyclization with good control of the spatial configuration of exocyclic double bonds. The novel [3+2+1]/[2+2+1] bicyclization resulted in 17 examples of unreported pyrazolo­[3,4-b]­pyrrolo­[4,3,2-de]­quinolones. Reasonable mechanisms for forming two new types of multicyclic pyrazolo­[3,4-b]­pyridines are also proposed. %I ACS Publications