BARC/PUB/09/0071

 
  Reductive deoxygenation of ortho-hydroxyaromatic aldehydes to 1,2-bis(hydroxyaryl)ethanes: application to the synthesis of ethylene bridged calixarene-analogous metacyclophanes  
     
 
Author(s)

Bhatt, S.; Nayak, S. K.

ABSTRACT

A novel and convenient protocol for the synthesis of hexahydroxy [2.1.2.1.2.1]- and octahydroxy [2.1.2.1.2.1.2.1] metacyclophanes from 4-substituted phenol in four steps has been developed. The synthetic route involved the preparation of the key intermediate 1,2-bis(5-substituted-2-hydroxyphenyl) ethanes in good yields via (i) formylation of 4-substituted phenol, (ii) reductive deoxygenation of 5-substituted 2-hydroxy aromatic aldehydes with low-valent titanium reagent and (iii) catalytic hydrogenation. The metacyclophanes were prepared by base-catalyzed macrocyclization of the above intermediates with formaldehyde in refluxing xylene in high yields.

 
 
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