ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The products isolated from the HOFMANN degradation of trans and cis 1,6-bis-trimethylammonio-cyclodecane (1a) depend on the reaction temperature. When carried out below 100° or when WITTIG'S low-temperature modification, i.e. with KNH2 in liquid ammonia, is employed, cyclodeca-l,5- and -1,6-dienes are formed almost exclusively, as shown by their hydrogenation to cyclodecane. When heated above 70° cyclodeca-l,5-diene (2) undergoes valency isomerisation to 1,2-divinylcyclohexane (4). This compound is obtained directly in ca. 45% yield besides 46% of non-isomerisable cyclodeca-l,5- and -1,6-dienes when the HOFMANN elimination is carried out at 120-150°. In addition, ca. 9% of octalines are formed by a transannular elimination reaction. The COPE elimination reaction of the bis-N-oxide of trans and cis 1,6-bis-dimethylarnino-cyclodecane (1c) at 120-150° affords a similar mixture of products containing ca. 43% of 1,2-divinylcyclohexane. The ease with which cyclodeca-l,5-diene undergoes valency isomerisation is attributed to the concomitant relief of strain and to the proximity of carbon atoms 1 and 6 in the trans/trans isomer.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19630460209
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