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Darstellung und Konformationsanalyse von 9,11‐Diphenyl[5](2,6)‐pyranophan‐10‐on
Author(s) -
Massa Werner,
Schween Michael,
Steuber Friedrich W.,
Wocadlo Sigrid
Publication year - 1990
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19901230722
Subject(s) - chemistry , sulfone , pyrolysis , crystal structure , allylic rearrangement , stereochemistry , proton nmr , medicinal chemistry , polymer chemistry , crystallography , organic chemistry , catalysis
Preparation and Conformational Analysis of 9,ll‐Diphenyl[5](2,6)‐pyranophan‐lO‐one Phanone 5 has been generated by pyrolysis of bis(sulfone) 4 . This reaction is the first example of a combined allylic‐aliphatic pyrolysis of bis(sulfones); it follows a two‐step mechanism, as is concluded from the absence of cross products and the formation of mono(sulfone) 5a as a by‐product. The flipping of the pentamethylene chain of 5 is unhindered at room temperature as shown by 1 H NMR. At 213 K this flipping process is slowed on the NMR time scale, and rotation about the C‐2C‐3 axis is no longer possible. The crystal structure of 5 shows the expected tub‐like conformation of the heterocycle.