ISSN:
0009-2940
Schlagwort(e):
Rearrangements, thermal
;
Propargyl-Cope reaction
;
1,5-Hexadiyne-3,4-diol
;
Cyclobutene
;
3,4-diacetyl
;
Fragmentations, retro-ene
;
Tandem reactions
;
Chemistry
;
Inorganic Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
The thermal behavior of meso- and d,1-3,4-dimethyl-1,5-hexadiyne-3,4-diol (meso- and d,1-4) has been studied at 400°C in the gas phase. In a tandem reaction the diols isomerize via the bisallenes 5 first to cis- and trans-3,4-diacetylcyclobutene (cis- and trans-8) which have been detected as intermediates by 13C-NMR spectroscopy as well as catalytic hydrogenation to 1,2-diacetylcyclobutane (9). Subsequently, 8 stabilizes itself by ring opening to (E,Z)- and (E,E)-3,5-octa-dien-2,7-dione (E,Z) and [(E,Z)-6]. As a side reaction retroene cleavage of 4 to 2-butynone (10) and methyl vinyl ketone (12) is observed. By pyrolysis of the pure diastereomers 4 it is shown that the retro-ene process is more pronounced in the d,l than in the meso series.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/cber.19941270526
