Versions of new reaction in the chemistry of organoaluminum compounds
| Autor: | Tolstikov Genrikh A, Marina P. Yakovleva, G. Yu. Ishmuratov, Yu. A. Galkina, R. R. Muslukhov, V. A. Vydrina |
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| Rok vydání: | 2014 |
| Předmět: | |
| Zdroj: | Russian Journal of Organic Chemistry. 50:1704-1707 |
| ISSN: | 1608-3393 1070-4280 |
| DOI: | 10.1134/s1070428014110311 |
| Popis: | Here we report on new versions of this reaction by the examples of adamantanolactone (XII), β-campholide (XIII), caranolactone (XIV), and also allobetulonolactone (XV) and norallobetulonolactone (XVI) obtained from betulin [3]. At the reduction of adamantanolactone (XII) isobutylacetal (VII) formed in 60% yield. β-Campholide (XIII) afforded a diastereomeric mixture (58 : 42 according to Н NMR data) of acetal VIII. In the stereochemical assignment of the NMR spectra of compound VIII the chemical shift values of the bridgehead carbon atoms (С, С) and those in the bottom of the boat (С, С), and also the chemical shifts and coupling constants of the anomeric proton Н are informative. Relatively downfield signals of the mentioned atoms С (~δ 1–2.5 ppm), and also more upfield shift of the anomeric proton Н at 5.06 ppm and a large value of J3,4 5.3 Hz indicate the equatorial orientation of the i-BuО group in the prevailing stereoisomer. According to Н NMR data compound IX formed as a mixture (3 : 1) of epimers with respect to asymmetric acetal center. The value J2,3 8.9 Hz of the anomeric proton in the predominant stereoisomer indicates its axial orientation and consequently the equatorial position of the isobutoxy group. |
| Databáze: | OpenAIRE |
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