Naphthalene-based calixarenes: Unusual regiochemistry of a Friedel-Crafts alkylation

[GRAPHICS] In the pursuit of naphthalene based calixarenes, a Friedel-Crafts alkylation with unusual regiochemistry was observed. Treatment of carbinol 14 with catalytic triflic acid was expected to produce calixarenes of the class represented by 16. Instead, the major product was cyclic trimer 15, in which alkylation of each naphthalene ring occurred at the electronically deactivated position. The structure of compound 15 was assigned by 2-D NMR studies.