Bi(OTf)3-catalyzed sp3 C–H functionalization of 2-alkyl azaarenes to isatylidene malononitriles has been achieved to give oxindoles containing an all-carbon quaternary center.
Enantioselective Cascade Reaction of α-Cyano Ketones and Isatylidene Malononitriles: Asymmetric Construction of Spiro[4<i>H</i>-pyran-oxindoles]
作者:Jin Xie、Wei-Long Xing、Feng Sha、Xin-Yan Wu
DOI:10.1002/ejoc.201600432
日期:2016.8
α‐Cyano ketones have been used for the first time as Michael donors in the construction of chiral spiro compounds. In the presence of only 2 mol‐% of a chiral multifunctional organocatalyst, chiral spiro[4H‐pyran‐oxindole] derivatives were prepared in excellent yields with good‐to‐excellent enantioselectivities. This method provides a new approach to the synthesis of chiral spirocyclic oxindoles.
The iron-catalyzed cross-dehydrogenative coupling (CDC) of C(sp3)–H/C(sp3)–H bonds to afford olefins by 4H elimination is described. This method employs air (molecular oxygen) as an ideal oxidant, and is performed under mild, ligand-free and base-free conditions. H2O is the only byproduct. Good tolerance of functional groups and high yields have also been achieved. Preliminary mechanistic investigations
Enantioselective construction of novel chiral spirooxindoles incorporating a thiazole nucleus
作者:L.-Y. Cui、Y.-M. Wang、Z.-H. Zhou
DOI:10.1039/c6ra14178a
日期:——
Asymmetric cascade Michael/cyclization reaction between 2-substituted thiazol-4-ones and 2-(2-oxoindolin-3-ylidene)malononitriles was investigated using a series of chiralbifunctional hydrogen-bonding organocatalysts. Good yields (up to 91%) and excellent enantioselectivities (up to 98% ee) were achieved by using a (1R,2R)-1,2-diphenylethane-1,2-diamine derived thiourea catalyst. This method provides an
An environmentally benign approach for the synthesis of 3,3′-pyrrolidonyl spirooxindole derivatives via a cascade Knoevenagel–Michael–cyclization multicomponent reaction
Knoevenagel–Michael–cyclization multicomponentreaction of isatin, malononitrile and α-isothiocyanato imide in the presence of a catalytic amount of triethylamine “on water” assisted with ultrasonic irradiation. The advantages of this method include high efficiency, mild reaction conditions and environmentallybenign reagents. The current process provides a simple and green method for creating diversity-oriented