کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1388488 | 1500850 | 2015 | 5 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Contact ion pairs and solvent-separated ion pairs from d-mannopyranosyl and d-glucopyranosyl triflates Contact ion pairs and solvent-separated ion pairs from d-mannopyranosyl and d-glucopyranosyl triflates](/preview/png/1388488.png)
• Ion pairs from a mannosyl triflate donor were studied at the DFT(M06-2X) level of theory.
• Oxacarbenium ions from the mannosyl donor preferred B2,5-like conformations to 4H3-like ones.
• Dioxacarbenium ions with a 1,6-anhydro structure are more stable in the mannosyl series than in the glucosyl one.
The chemical nature of contact ion pairs and solvent-separated ion pairs from 2,3,4,6-tetra-O-methyl-α-d-mannopyranosyl triflate was investigated at the DFT(M06-2X) level of theory. Comparison of the present results to those obtained for the d-glucopyranosyl counterpart in our previous study indicated that the ion pairs from the d-mannopyranosyl triflate adopt B2,5-like conformations more preferably than those from the d-glucopyranosyl triflate. Similarly, 1,6-anhydro-d-mannopyranosyl dioxacarbenium ions bearing a 1C4 conformation were shown to be more stable than the d-glucopyranosyl counterparts.
Figure optionsDownload as PowerPoint slide
Journal: Carbohydrate Research - Volume 401, 12 January 2015, Pages 127–131