Fragment Condensation Synthesis of Calixarenes

A 2 -I- 2 fragment condensation of 41 and 42 has been employed in the synthesis of calix[4]arenes 43 carrying substituents (R and/or R = Me, Et, 

Other recent examples of convergent procedures include the 2 -f- 2 reaction to give a 

For a method of synthesis of unsymmetrical l,l-bis(2-hydroxyaryl)alkanes, see Katritzky, A. R.  

Griittner, C. Bohmer, V. Vogt, W. Thondorf, 1. Biali, S. E., Grynszpan, F. Tetrahedron Lett. 

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