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3‐Fluoro‐2,4‐dioxa‐7‐aza‐3‐phosphadecalin 3‐Oxides as Rigid Acetylcholine Mimetics: Conformational Analysis and Direct Evidence of the Anomeric Effect
Author(s) -
Furegati Stefan,
Binder Martin,
Linden Anthony,
Rüedi Peter
Publication year - 2006
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200690135
Subject(s) - chemistry , epimer , decane , conformational isomerism , anomer , anomeric effect , substituent , stereochemistry , cyclohexane conformation , moiety , crystallography , solid state , crystal structure , envelope (radar) , molecule , organic chemistry , hydrogen bond , telecommunications , radar , computer science
Conformational analyses of the P(3)‐axially and P(3)‐equatorially F‐substituted (±)‐ cis‐ and (±)‐ trans‐ 2,4‐dioxa‐7‐aza‐3‐phosphadecalin 3‐oxides (3‐fluoro‐2,4‐dioxa‐7‐aza‐3‐phosphabicyclo[4.4.0]decane 3‐oxides) were performed. The results are based on independent studies in both solution and the solid state by 1 H‐ and 31 P‐NMR experiments and computational and X‐ray crystallographic data. As expected, the axial epimers adopt neat double‐chair conformations in solution and in the crystal. Due to the anomeric effect of the electron withdrawing F‐substituent, the 2,4‐dioxa‐3‐phospha moiety in the equatorial epimers adopts a mixture of conformations in solution, mainly chair and twist‐boat; whereas a neat twist‐boat ( trans‐ isomer) and the unusual envelope conformation ( cis‐ isomer) were detected in the solid state. This is the first report of a straight visualization of these conformations and the impact of the anomeric effect in such systems.