Asymmetric diels - alder reactions with α-chloronitroso compounds - I. Application of α-chloronitroso epiandrosterone in synthesis
✍ Scribed by Mahmud Sabuni; Günter Kresze; Heinz Braun
- Publisher
- Elsevier Science
- Year
- 1984
- Tongue
- French
- Weight
- 231 KB
- Volume
- 25
- Category
- Article
- ISSN
- 0040-4039
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✦ Synopsis
The Diels -Alder reaction of 1,3-cyclohexadiene (9) with the enanticmerically pure cc-chloronitroso compound 8, synthesized from epiandrosterone-(7a), gives the adduct 10a with l-(R),4-(S) configuration-in 69 % chemical yield andz95 % enazicmeric excess.
📜 SIMILAR VOLUMES
The structure of the a-chloronitroso ether I, obtained from the hydroximolactone 2 and tert-butyl hypochlorite (89 %), was established by X-ray crystallographic analysis. The [4 + 2 1 cycloadditions of 1 with the dienes 3 and %I1 led to the N-unsubstituted 3,6-dihydro-2H-1,2-oxazines 6 and 12-16 in
The Diels-Alder reaction of 1,3-cyclohexadiene with the a-chloro-a-nitroso ether 2, prepared from mannose via the lactone oxime 1, gives the adduct 3 with l-(S),4-(R) configuration in 69 % chemical yield and z 95 % enantiome& excess.
Transient, chiral u-hydroxyacylnitroso compounds (2), able to form intramolecular hydrogen bonds, react stereoselectively with cyclopentadiene and cyclohexa-1,3-diene; the cycloadduct (6) of the latter diene and the nitroso derivative of (S)-mandelic acid has been converted into the known (-)-oxazin
## Abstract The α‐chloronitroso compounds **1a–1f** were made to react with methyl and phenyl Grignard reagents. N‐methyl and N‐phenyl substituted ketonitrones **2** and **3** were obtained in 48‐78% yield. The structure of these labile nitrones is based on their spectroscopic properties and on the