Starting from (R)-(+)-and from (S)-(-)-camphor the chiral alcohols 1: 2 and 3 have been prepared; their acrylates II underwent TiCl,(OR),-promoted Diels-Alder additTons to cyclopentadiene giving efficiently in a predictable manner either the (2R)-or the (2S)-adducts III with up to virtually quantita
Asymmetric diels-alder reactions of acrylates derived from 3-alkyl-borneols and -isoborneols
โ Scribed by Wolfgang Oppolzer; Christian Chapuis
- Publisher
- Elsevier Science
- Year
- 1984
- Tongue
- French
- Weight
- 177 KB
- Volume
- 25
- Category
- Article
- ISSN
- 0040-4039
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โฆ Synopsis
Starting from (+)-camphor the chiral alcohols 1 and 8 have been prepared; their acrylates 9 and 13 underwent TiC12(0iPr)
-mediated Diels-Alder additions to cyclopentadiene zth stereoface-differen 3, iations of 66% d.e. and 94% d.e., respectively.
๐ SIMILAR VOLUMES
## Abstract Starting from the enantiomerically pure monoterpenes (+)โpulegone (**3**), (+)โlimonene (**7**), (โ)โฮฒโpinene (**9**), (+)โ and (โ)โcamphor (**13**) or (+)โcholestenone (**11**) the chiral alcohols **4, 5, 6, 8, 10, 12, 14, 15, 16, 17** et **18** were prepared; their acrylates **II** un
The crystalline chiral auxiliaries 4 and 5 were readily prepared from camphorsulfonic acid. Their acrylates underwent the Diels-Alder reactions 5 + 7 with modest asymmetric induction consistent with an X-ray study of k.
In the presence of a cinchona alkaloid as a catalyst, the Diels-Alder reaction of 3-hydroxy-2-pyrone with chiral N-acryloyl oxazolidinone afforded a bicyclolactone adduct with high diastereoselectivities (up to 95%de) in almost quantitative yield.