
%0 Journal Article
%A Bell, Stephanie E. V. 
%A Brown, Roger F. C. 
%A Eastwood, Frank W. 
%A Horvath, Julianna M. 
%T An Approach to Some Spiro Oxindole Alkaloids Through Cycloaddition Reactions of 3-Methylideneindolin-2-one
%J Australian Journal of Chemistry
%D 2000/06/26
%V 53
%N 3
%P 183-190
%K Carbamate; flash vacuum pyrolysis; indole; synthesis; ylide.
%R https://doi.org/10.1071/CH00016
%U https://www.publish.csiro.au/paper/CH00016 
%X 3-Methylideneindolin-2-one (3-methylideneoxindole) (1) was prepared in 60&#8211;89% yield by flash vacuum pyrolysis of the acetate or methyl carbonate of 3-hydroxy-3-methylindolin-2-one, and was fully characterized, but application of the same procedure to 3-hydroxy-5-methoxyindolin-2-one did not give useful yields. Cycloaddition reactions of CH2= +NR&#8211;CH2 &#8211; and of the related ylide (25) (from 1-(trimethylsilylmethyl)piperidine-2-carbonitrile and AgF) to 3-methylideneindolin-2-one (1) gave 4&#8211;20% yields of spiro oxindoles, but yields were markedly below those achieved in cycloadditions to the more electrophilic N-phenylmaleimide (70&#8211;79%). Attempted alkylation of weakly basic secondary amines, e.g. piperidine-2-carbonitrile, with Me3SiCH2Cl in dimethyl sulfoxide/K2CO3 gave only carbamates Me3SiCH2OOCNR2. 
