Synthesis, Conformational Analysis and Transannular Reactions of 5,9-Propanobenzo[7]annulene Derivatives

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Title:Synthesis, Conformational Analysis and Transannular Reactions of 5,9-Propanobenzo[7]annulene Derivatives
Creators:
Camps, Pelayo
Görbig, Diana
Muñoz-Torrero, Victoria
Pérez, Francesc
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 62, 10, pp. 1585-1598
Uncontrolled Keywords:5,9-Propanobenzo[7]annulene derivatives, Annulenes, Transannular reactions, Conformational analysis

Abstract

(5α,9α,11β)-11-Hydroxy-6,7,8,9-tetrahydro-5<i>H</i>-5,9-propanobenzo[7]annulen-7-one ethylene ketal (<strong>6a</strong>) and its 11α-methyl derivative (<strong>6b</strong>) were prepared from monoketal <strong>3</strong>. These compounds underwent acid-catalyzed transannular reactions leading to 6,7,8,9-tetrahydro-5<i>H</i>-5,9-propanobenzo[7]annulene derivatives <strong>5a</strong>, <strong>8a</strong> and <strong>5b</strong>, <strong>8b</strong>, respectively, depending on the reaction conditions. The compounds <strong>6a</strong> and <strong>6b</strong> were dehydrated to 6,7,8,9-tetrahydro-5H-5,9-prop[1]enobenzo[7]annulen-7-one (<strong>9a</strong>) and its 11-methyl derivative (<strong>9b</strong>), respectively. The conformational analysis of the 5,9-propanobenzo[7]annulene derivatives by molecular mechanics calculations (MM3 program) and the <sup>1</sup>H NMR data show that hydroxyketal <strong>6a</strong> and the related compound (5α,7β,9α)-6,7,8,9-tetrahydro-5<i>H</i>-5,9-propanobenzo[7]annulen-7-ol (<strong>4</strong>) exist mainly in the <i>boat</i>-<i>chair </i>conformation with the <i>boat </i>cycloheptenol ring, while for hydroxyketal <strong>6b</strong> the <i>chair</i>-<i>boat </i>conformation (<i>chair </i>cycloheptenol ring) seems to be the preferred one.

Title:Synthesis, Conformational Analysis and Transannular Reactions of 5,9-Propanobenzo[7]annulene Derivatives
Creators:
Camps, Pelayo
Görbig, Diana
Muñoz-Torrero, Victoria
Pérez, Francesc
Uncontrolled Keywords:5,9-Propanobenzo[7]annulene derivatives, Annulenes, Transannular reactions, Conformational analysis
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:62
Number:10
Page Range:pp. 1585-1598
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19971585UNSPECIFIED
ID Code:1234
Item Type:Article
Deposited On:06 Feb 2009 17:07
Last Modified:06 Feb 2009 16:07

Citation

Camps, Pelayo; Görbig, Diana; Muñoz-Torrero, Victoria; Pérez, Francesc (1997) Synthesis, Conformational Analysis and Transannular Reactions of 5,9-Propanobenzo[7]annulene Derivatives. Collection of Czechoslovak Chemical Communications, 62 (10). pp. 1585-1598. ISSN 0010-0765

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