A Conformational Analysis of 2-(X), 4-(Y)-Substituted Pentanes (X, Y = OH, SH), Using Chiroptical Properties and 1H NMR Spectroscopy
✍ Scribed by L. I. Spiessens; C. Becu; N. Hosten; F. Anteunis-De Ketelaere; M. J. O. Anteunis; D. Tavernier
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 2010
- Weight
- 664 KB
- Volume
- 91
- Category
- Article
- ISSN
- 0037-9646
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✦ Synopsis
Abstract
Optically active threo‐(2S,4S)‐4‐mercapto‐2‐pentanol, erythro‐(2R,4S)‐4‐mercapto‐2‐pentanol and threo‐(2S,4S)‐pentanedithiol, were prepared from threo‐(2R,4R)‐pentanediol. The mechanism of their formation is discussed. The molecular optical rotation [M]~D~ of these compounds, of trans‐(4S,6S)‐, cis‐(4S,6S)‐dimethyl‐1,3‐oxathiane and of trans‐(4S,6S)‐dimethyl‐1,3‐dithiane, was determined and was related to the composition of the conformational mixture using Brewster's conformational rotatory power model.
A complete conformational analysis of the six 2‐(X)‐4‐(Y)‐substituted pentanes (X,Y = OH, SH) was obtained from their ^1^H NMR spectra in combination with their chiroptical properties. The threo compounds favour the aa conformation, whereas the ag^−^/g^+^a forms are prefered in the erythro isomers, except for the 2,4‐diols where the intramolecular hydrogen bonded form is predominant.