The Use of Anhydrous Barium Hydroxide for Selective Alkylation of Dialkyloxy-tert-butyl-calix[4]arenes

A practical method of selective alkylation of the third hydroxyl group of disubstituted tert-butyl-calix[4]arenes using anhydrous barium hydroxide as a base was developed in this study. The use of this method in the synthesis of inherently chiral derivatives is shown herein

The Use of Anhydrous Barium Hydroxide for Selective Alkylation of Dialkyloxy-<i>tert</i>-butyl-calix[4]arenes

A practical method of selective alkylation of the third hydroxyl group of disubstituted tert-butyl-calix[4]arenes using anhydrous barium hydroxide as a base was developed in this study. The use of this method in the synthesis of inherently chiral derivatives is shown herein

Chiral phosphorus-containing calixarenes

International audiencePhosphorus-containing inherently chiral calix[4]arenes as well as calix[4]arenes substituted with phosphinoferrocene chiral groups at the lower rim are described. Stereoselective synthesis, structure, and catalytic properties of the chiral calixarenes are discussed

Synthesis of an Enantiomerically Pure Inherently Chiral Calix[4]Arene Phosphonic Acid and Its Evaluation as an Organocatalyst

A facile method for the preparation of enantiomerically pure inherently chiral calix[4]­arene phosphonic acid (<i>cR</i>,<i>pR</i>)-<b>7</b> in four steps starting from the readily available and previously synthesized (<i>cS</i>)-enantiomer of calix[4]­arene acetic acid <b>1</b> or its methyl ester <b>2</b> was developed. The first tests of this unique calixarene Brönsted acid with inherent chirality in organocatalysis of the aza-Diels–Alder reaction of imines with Danishefsky’s diene and epoxide ring opening by benzoic acid were performed. The calixarene phosphonic acid (<i>cR</i>,<i>pR</i>)-<b>7</b> shows good catalytic activities but with low enantioselectivities in these reactions