Methylene-indolinones

Methylene)indolinones have also been prepared by a tandem Heck-carbonylation/Suzuki-coupling [165]. Even though this methodology was further developed with Pd(PPh3)4, the combination Pd(OAc)2/SlPr HBF4 showed comparable activity (Scheme 19). 

Recently, this catalytic system was further applied in an enantioselective 1,3-dipolar cycloaddition of nitrile imines 47 with methylene indolinones 26. Stanley et al. prepared the 39c-Mg(NTfa)2 catalyst and used 10 mol% of it to promote the process, providing the corresponding adducts 48 in 63-91% pelds and with 61-99% enantiomeric excess (Scheme 3.14). ... 

Although heterocycUc ortho-quinodimethanes (oQDMS) have been studied extensively to design Diels-Alder reactions for the synthesis of complex indole alkaloids for more than 30 years, asymmetric catalysis of the Diels-Alder reaction of nitroolefins 32 or methylene-indolinones 39 with in situ generated heterocyclic... 

Hydrogen-bonding catalysis of the Diels-Alder reaction of 2-vinylindoles 39 and methylene-indolinones 69 has been accomplished by the Barbas group using a C2-symmetric bis-thiourea organocatalyst [31]. This efficient transformation provided a powerful approach by which to construct carbazole-spirooxindole derivatives 71 extremely rapidly (less than 10 min) with excellent enantiopurity and structure diversity (Scheme 38.20). 

Scheme 42.45 Phosphoric acid-catalyzed enantioselective synthesis of spirooxindoles by enantioselective domino 1,3-dipolar cycloaddition of in situ formed azomethine ylides and methylene-indolinones.

Other electrophiles such as succinic anhydride," imines," " or 2-(2-amino-methylene)-3-indolinones" have also been used to prepare 5(47f)-oxazolones. 

The base-catalyzed reaction at the activated methylene positions of the pyrrolinones and indolinones with aromatic aldehydes is a general reaction producing the benzylidene derivatives. Products of the Ehrlich reaction with pyrrolinones are generally yellow-orange... 

In 1-ethyl-3-methylene-2-indolinone dichlorotriphenylphosphine substitutes the methylene group by a phosphine group with the formation of compound 132 [123], and in di- and trialkylindoles it reacts at the 3-CH3 group with the formation of compound 133 [124] ... 

The stereocontroiied total synthesis of (+)-gelsemine was accomplished by T. Fukuyama and co-workers using the Knoevenagel condensation to prepare a precursor for the key divinylcyclopropane-cycloheptadiene rearrangement. The use of 4-iodooxindole as the active methylene component allowed the preparation of the (Z)-alkylidene indolinone product as a single stereoisomer. 

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