Issue 6, 2015

Can acyclic conformational control be achieved via a sulfur–fluorine gauche effect?

Abstract

The gauche conformation of the 1,2-difluoroethane motif is known to involve stabilising hyperconjugative interactions between donor (bonding, σC–H) and acceptor (antibonding, σ*C–F) orbitals. This model rationalises the generic conformational preference of F–Cβ–Cα–X systems (ϕFCCX ≈ 60°), where X is an electron deficient substituent containing a Period 2 atom. Little is known about the corresponding Period 3 systems, such as sulfur and phosphorus, where multiple oxidation states are possible. Conformational analyses of β-fluorosulfides, -sulfoxides and -sulfones are disclosed here, thus extending the scope of the fluorine gauche effect to the 3rd Period (F–C–C–S(O)n; ϕFCCS ≈ 60°). Synergy between experiment and computation has revealed that the gauche effect is only pronounced in structures bearing an electropositive vicinal sulfur atom (S+–O, SO2).

Graphical abstract: Can acyclic conformational control be achieved via a sulfur–fluorine gauche effect?

Supplementary files

Article information

Article type
Edge Article
Submitted
10 Mar 2015
Accepted
16 Apr 2015
First published
17 Apr 2015
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2015,6, 3565-3571

Author version available

Can acyclic conformational control be achieved via a sulfur–fluorine gauche effect?

C. Thiehoff, M. C. Holland, C. Daniliuc, K. N. Houk and R. Gilmour, Chem. Sci., 2015, 6, 3565 DOI: 10.1039/C5SC00871A

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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