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Synthesis and Conformational Studies of Novel Calixarene‐Analogous Macrocyclic [3.1.1]Metacyclophanes
Author(s) -
Yamato Takehiko,
Doamekpor Louis Korbla,
Tsuzuki Hirohisa
Publication year - 1997
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.199719970733
Subject(s) - chemistry , conformational isomerism , calixarene , yield (engineering) , amide , proton nmr , intramolecular force , alkylation , stereochemistry , organic chemistry , catalysis , molecule , materials science , metallurgy
Hydroxy[3.1.1]metacyclophane 4c , which is regarded as an unsymmetric or uncomplete “homocalixarene” bearing a propane bridge, has been synthesized using Nafion‐H catalyzed cyclobenzylation. A novel “pendulum” type motion steered by intramolecular hydrogen bonding has been observed Demethylation of compound 4c with BBr 3 in methylene dichloride was carried out at room temperature for 3 h to afford the dihydroxy[3.1.1]metacyclophane 4b in 74% yield along with the triol 4a in 25% yield. Triol 4a was tri‐ O ‐alkylated with methyl iodide in the presence of NaH to yield partial‐cone conformer 4d in quantitative yield. Similarly, a significant amount of partial‐cone conformer 5 results in the case of O ‐alkylation of 4a with N , N ‐diethylchloroacetamide. 1 H‐NMR titration of partial‐cone amide 5 with NaSCN clearly demonstrates that a 1:1 complex is formed which is stable on the NMR time scale.