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An Efficient Synthetic Approach to Calix[ n ]furan[4‐ n ]pyrroles and the Calix[ n ]tetrahydrofuran[4‐ n ]pyrrolidines
Author(s) -
Maupillier William,
Journot Guillaume,
StoeckliEvans Helen,
Neier Reinhard
Publication year - 2017
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201701156
Subject(s) - tetrahydrofuran , chemistry , furan , calixarene , medicinal chemistry , organic chemistry , stereochemistry , molecule , solvent
A scalable synthesis of calix[ n ]furan[4‐ n ]pyrroles and their fully reduced analogues, calix[ n ]tetrahydrofuran[4‐ n ]pyrrolidines obtained by hydrogenation of their aromatic relatives, was developed and optimized. The hydrogenation reaction was studied at several selected pressures (P = 100, 50 and 15 bars) and high diastereoselectivity was observed for the four possible calix[ n ]tetrahydrofuran[4‐ n ]pyrrolidines. Moreover, two of the saturated macrocycles were obtained with good overall yields starting from easily accessible calix[4]furan. The conformation of the eight macrocycles was analyzed by X‐ray diffraction and although a classical 1,3‐alternate conformation of this type of compound was observed for the aromatic macrocycles, two distinct types of conformation were observed with the calix[ n ]tetrahydrofuran[4‐ n ]pyrrolidines.