Low catalyst loading enabled organocatalytic synthesis of chiral bis-heterocyclic frameworks containing pyrazole and isoxazole.

The organocatalytic asymmetric synthesis of enantiopure bis-heterocyclic molecules containing pyrazole and isoxazole under mild reaction conditions has been reported a low-catalyst loading Michael addition reaction of pyrazolyl nitroalkenes with 1,3-dicarbonyl derivatives. 4-Substituted pyrazole derivatives were obtained in 60-87% yields and with 82-97% ee. These pyrazolyl derivatives are further transformed into chiral bis-heterocyclic derivatives in up to 82% yields and up to 99% ee.

Arenesulfonyl indole: new precursor for diversification of C-3 functionalized indoles.

Arenesulfonyl indoles, bearing a good leaving group, are effective precursors for vinylogous imine intermediates which are generated under basic conditions. This intermediate can readily react with other nucleophilic reagents to obtain C-3 substituted indole derivatives. In the last few years, a plethora of exciting synthetic applications of this substrate have been exploited.

Recent advances in the catalytic synthesis of 3-aminooxindoles: an update.

3-Substituted-3-aminooxindoles are versatile scaffolds and they are common core structural motifs found in many natural products and biologically active compounds. In the last few years, a variety of synthetic methodologies have been developed for the synthesis of this moiety. In this review, we are presenting the recent advances in the catalytic synthesis of 3-aminooxindole derivatives.

2,4-Dinitrophenol-Catalyzed α-C(sp(3) )-H and C(sp)-H Bond Functionalization of Cyclic Amines and Alkynes: Highly Regio-/Diastereoselective Synthesis of α-Alkynyl-3-Amino-2-Oxindoles.

A transition-metal- and oxidant-free DNP (2,4-dinitrophenol)-catalyzed atom-economical regio- and diastereoselective synthesis of monofunctionalized α-alkynyl-3-amino-2-oxindole derivatives by C-H bond functionalization of cyclic amines and alkynes with indoline-2,3-diones has been developed. This cascade event sequentially involves the reductive amination of indoline-2,3-dione by imine formation and cross coupling between C(sp(3) )-H and C(sp)-H of the cyclic amines and alkynes. This reaction offers an efficient and attractive pathway to different types of α-alkynyl-3-amino-2-oxindole derivatives in good yields with a wide tolerance of functional groups.