Stereoselective conjugate addition of propionate Ti ate enolate to unsaturated chiral ketones: A new insight in the reaction mechanism
✍ Scribed by Anna Bernardi; Chiara Marchionni; Tullio Pilati; Carlo Scolastico
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- French
- Weight
- 275 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0040-4039
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✦ Synopsis
We ncently qorted that Ti "ate" complexes of ketone and ester cnolatcs. obtain& by treating tbc axresponding Li cnolates with 1 mol a@ of Ti(OiPr)g, acid to unsacur8ad carbonyl compounds in a 1.4 fashion with high rcgi~ and stereose lectivity and offer various advantages in comparison with their Li counterparts.t For ketone enolates. the use of the Ti complexes improves both the ngioselcctivity and tbc suraiselectivity of the coqjugate addition. The sense of selectivity is the same as for Li (i.e. when adding toE CW. E enolates afford syn canpounds, andZenolatcslheMtj isanas).~OnthecOntray,fC!SC!4tWWlatCS the stuwchcmicaloutcumcofthcadditionismuscdongoingfmm LitolI.RxinstancGtbc~coolatcof