The electron-releasing homoconjugated carbonyl group. Application to the total syntheses of 3-deoxy-, 4-deoxy-hexose, lividosamine and derivatives
✍ Scribed by Daniela Fattori; Etienne de Guchteneere; Pierre Vogel
- Book ID
- 104212370
- Publisher
- Elsevier Science
- Year
- 1989
- Tongue
- French
- Weight
- 298 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0040-4039
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✦ Synopsis
The regioselective electrophilic addition of benzeneselenyl bromide to (-)-(lS,4S)-7~oxabicyclo/2.2.lihept-S-en-2-one were exploited to develop efficient syntheses of methyl 3-deoxy-a-D-arabino-hexofuranoside and 4-deoxy-D-lyxo-hexopyraose. Similarly, D-lividosamine (3-deoxy-D-glucosamine) was derived from (+)-(lR,4R)-7-oxabicyclo/2.2.llhept-S-en-Z-one. In a recent publication on the solvolysis of 3-oxobicyclo[2.2.2]oct-I-yl triflates, Takeuchi and Ynshida' claimed to have discovered the first example of the through-bond interaction of the P-carbonyl lone pair with a cationic p orbital. Already in 1982, we reported* on the electrophilic additions of enones I that give exclusively adducts 5 under conditions of kinetic control. The results were interpreted in terms of electron-releasing homoconjugated carbonyl group (2 c--f 3 -4) due to favourable n(CO)-cs(C(l),C(2))-K(6) hyperconjugative