| Autor: |
Bubnov, Yury N., Zhun', Ilya V., Klimkina, Elena V., Ignatenko, Anatoly V., Starikova, Zoya A. |
| Zdroj: |
European Journal of Organic Chemistry; October 2000, Vol. 2000 Issue: 19 p3323-3327, 5p |
| Abstrakt: |
Indoles undergo reductive α-allylation upon treatment with allylic boranes (triallyl- and triprenylborane) to give, after deboronation, the corresponding 2-allylated indolines in 70−85% yield. 1,2-Addition of the allylboron fragment to heterocycles occurs with full rearrangement of the allylic moiety. Reductive prenylboration of 3-substituted indoles, as well as allylboration of 3-isopropylindole, with All3B proceed stereoselectively to produce trans-2,3-disubstituted indolines only, while similar reactions of triallylborane with 3-R-indoles, containing a primary group R, afford a mixture of trans (86−92%) and cis isomers (8−14%). From 1-deuterioindole and triallylborane, a mixture of cis- and trans-2-allyl-3-deuterioindole in a ratio of 1:1 was obtained. Proposed mechanism of the general reaction involves intermediate formation of 3H-indole tautomers followed by fast allylboration of the C=N bond. Structures of trans-indolines 3b and 3c were confirmed by X-ray analysis. |
| Databáze: |
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