Calix[6]resorcinarenes: the first examples of [16]metacyclophanes derived from resorcinols

Abstract

The cyclocondensation of 2-alkylresorcinols with 1,3,5-trioxane in ethanol-conc. HCI (4: 1 v/v) produced calix[4lresorcinarerie and calix[6]resorcinarene; the latter was isomerized to the former on prolonged heating in the reaction media.

Metallo-supramolecular capsules

“…The general acid catalysed condensation used to form Calkylresorcin [4]arenes, C-alkylpyrogallol [4]arenes and C-haloalkylpyrogallol- [4]arenes [89,90]. Konishi et al synthesised resorcin [4,5 and 6]arenes by reacting 2-alkylresorcinols with trioxane or formaldehyde diethyl acetal (Scheme 2A) [91]. Following this study, Sherman and co-workers synthesised a series of expanded [n]cavitands where n ≥ 4 (Scheme 2B).…”

Cyanoresorc[5]arenes: Isolation, Conformation and Crystal Structure

“…Three different, novel, highly flexible stereoisomers were obtained instead of the cone conformations previously obtained for resorc [5]arenes [2] and [5]cavitands. [3] Furthermore, although tetramer formation affords distinct conformations, pentamer formation gives more complex and less defined architectures, both in solid and in gas phases.…”

“…Although most attention during the past twenty years has been devoted to the calix [4]arenes, larger members such as calix [5]arenes [1b] and calix [6]arenes [1e] have raised some interest. Konishi et al [2] reported the synthesis of resorc [5]arenes and resorc [6]arenes by acidcatalysed condensation of 2-propylresorcinol with formaldehyde diethyl acetate, whilst Sherman et al, [3] utilizing 2-methylresorcinol and diethoxymethane as starting materials, recently synthesized [n]cavitands with n Ն 4. In both cases the compounds containing five aromatic subunits had highly symmetric cone conformations.…”

Resorcinarenes as Templates

“…Access to other resorcinarenes could open the way to the templation of larger macrocycles, and in this regard, the determination of processes that allows the isolation of resorcinarenes that contain five, six, and seven resorcinol rings is of considerable interest. [43,44] Most recently, these resorcinarenes have also been converted to their corresponding methylene bridged cavitands, for example, 16.…”