Stereochemistry of base-catalyzed hydrogen exchange in cyclic sulfonium salts
Journal Article
·
· Journal of the American Chemical Society
The relative rate constats of succeesive H/D exchange at carbons next to sulfur for the four alpha -methylene hydrogens in thiacyclohexylmethylsulfonium iodide (3) and thiacyclopentylmethylsulfonium iodide (2) with sodium deuterixide in D2O have been measured. The reactivity ratio for the two pairs of diastereotopic hydrogens in the six-membered ring (3) is near 1: 1, but in the five-membered ring (2) it is ca. 12: 1. The corresponding ratio for the two diastereomeric 2-methylthiacyclohexylmethylsullonium salts 4 and 5 at the methylene carbon is about the same as for the parent compound 3. The results for the thiacyclohexyl compound 3 agree with those found by others but those for the thlacyclopentyl compound 2 are onl~ in qualitative agreement, the selectivity being less by a factor of over 30 than reported earlier. The findings are discussed in relation to the present status of the gauche effect.
- Research Organization:
- Univ. of Notre Dame, IN
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-29-009900
- OSTI ID:
- 4414907
- Journal Information:
- Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 24 Vol. 95; ISSN 0002-7863
- Publisher:
- American Chemical Society (ACS)
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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