ISSN:
0009-2940
Keywords:
Pyranophanones
;
Sulfone, pyrolysis
;
Ring strain
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Preparation and Conformational Analysis of 9,ll-Diphenyl[5](2,6)-pyranophan-lO-onePhanone 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 1H NMR. At 213 K this flipping process is slowed on the NMR time scale, and rotation about the C-2—C-3 axis is no longer possible. The crystal structure of 5 shows the expected tub-like conformation of the heterocycle.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19901230722
