| Autor: |
Bubnov, Yu., Klimkina, E., Lavrinovich, L., Zykov, A., Ignatenko, A. |
| Zdroj: |
Russian Chemical Bulletin; Sep1999, Vol. 48 Issue 9, p1696-1706, 11p |
| Abstrakt: |
Pyrrole undergoes reductive mono- and diallylation on successive treatment with β,γ-unsaturated organoboron derivatives (triallylborane, allyl(dipropyl)borane, and triprenylborane) and alcohols to give 2-allylated 3-pyrrolines and trans-2,5-diallylated pyrrolidines. The addition of both the first and second boron-allylic fragment to the heterocycle proceeds with rearrangement. A method for transformation of the trans-2,5-diallylpyrrolidine into the cis-isomer (heating with triallylborane at 190 °C) was developed and a series of N-substituted derivatives of these pyrrolidines was synthesized. A method for the preparative synthesis of nonsymmetrically substituted trans- and cis-2-alkyl(phenyl)-5-allylpyrrolidines, based on reductive allylboration of pyrrole followed by 1,2-addition of RLi to the 5-allyl-1-pyrroline that formed, was also developed. A direct confirmation of intermediate formation of 2 H- and 3 H-pyrrole tautomers under the action of allylboranes was obtained. The adduct of 2 H-pyrrole with BF3 was detected by NMR spectroscopy. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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