Amathia convolute

The use of bifunctional catalyst 60d (10 mol%) has permitted the synthesis of several 3-alkyl-3-hydroindolin-2-ones (73) by reaction of acetone (13.6 equiv.) or butanone with a variety of isatins 72 (Scheme 4.22). The addition of acetic acid (20 mol%) as co-catalyst was required to achieve good results. For the case of the reaction with butanone, the process was highly regioselective affording mainly product 73d and 73e. Convolutamydine A, an alkaloid isolated from floridian marine bryozoan Amathia convolute, was prepared by reaction of acetone (3a) with 4,6-dibromoisatin (R =4,6-Brj and =H in 72) catalyzed by compound 60d under similar conditions, with product of type 73 being isolated in practical quantitative yield and 60% ee [134]. 

Garden, Tomasini, and co-workers [5] described the organocatalytic aldol reaction of acetone with dibromoisatin 1 to synthesize (/f)-convolutamydine A (3) (Scheme 17.1), a group member of alkaloids (convolutamydine A-E) isolated from the Floridian marine bryozoan Amathia convolute in 1995 with a potent inhibitory activity toward the differentiation of promyelocytic HL-60 human leukemia cells [6]. Using 10mol% D-prohnamide catalyst 2, (/ )-convolutamydine A (3) was obtained with just modest enantioselectivity (68% ee), but with high enantioselectivity (97% ee) after crystallization [7]. 

Zhang HP, Kamano Y, Ichihara Y, Kizu H, Komiyama K, Ito-kawa H, Pettit GR. Isolation and structure of convolutamy-dines B D from marine bryozoan Amathia convolute. Tetrahedron 1995 51 5523-5528. 

Kamano Y, Kotake A, Hashima H, Hayakawa I, Hiraide H, Zhang HP, Kizu H, Komiyama K, Hayashi M, Pettit GR. Three new alkaloids, convolutamines F and G, and convolutamydine E, from the Floridian marine bryozoan Amathia convolute Collect. Czech. Chem. Common. 1999 64 1147-1153. 

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See also in sourсe #XX -- [ ]

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