Selective formylation of calix[4]arenes at the ‘upper rim’ and synthesis of new cavitands

Abstract

The direct selective upper rim 1,3-formylation of conformationally rigid calix [4]arenes is achieved for the first time; the diametrical bis(formyl)calix[4]arene 4 is used as a key intermediate for the synthesis of new cavitands.

Novel Chiral (Salen)MnIII Complexes Containing a Calix[4]arene Unit as Catalysts for Enantioselective Epoxidation Reactions of (Z)‐Aryl Alkenes

“…To a chilled solution of cone 5-hydroxy-25,26,27,28-tetrapropoxycalix [4]arene [24] (1) (0.8 g, 1.32 mmol) in dry CH 2 Cl 2 (100 mL) was added Cl 2 CHOCH 3 (2.34 mL, 26.4 mmol) under N 2 . A 1 m solution of SnCl 4 in CH 2 Cl 2 (1.32 mL, 1.32 mmol) was then added and after 3-4 minutes the reaction was stopped with 1 m HCl.…”

Synthesis and Metal Complexation of Twovic-Dioxime Derivatives of Calix[4]Arenes

“…110 "C(dec.). IH Downloaded by [Gazi University] at 02:31 04 November 2014 NMR (CDCl,): 6 = 11.5 (2H, S, OH), 6.6-7.8 (64H, m, ArH of calix [4]arene, benzoyl and iminobenzyl groups, C-NH), 3.5-4.1(20H, broad, -CH2). The IR and elemental analyses of (2) are given in Tables I and II Tables I and 11.…”

“…Three phenolic groups of calix [4]arene were first benzoyllated by a procedure described in the literaturelg. This compound was than reacted with p-nitrobenzylbromide in the presence of K2C03 to yield compound (3).…”

“…In the present work, we report the synthesis of two novel calix [4]arenes substituted with vic-dioximes ( Fig. 1) and their complexes with Ni(II), Cu(II), and Co(II) ions.…”

New Formylating Agents − Preparative Procedures and Mechanistic Investigations

“…The comparable method with dichloromethyl methyl ether often employs a large excess of the formylating mixture (up to 18 equiv. ), [16,17] and the regioselectivity is rather low. [18] …”