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Studies on Lewis‐Acid Induced Reactions of 8‐Methoxy[2.2]metacyclophanes: A New Synthetic Route to Alkylated Pyrenes
Author(s) -
Monarul Islam Md.,
Feng Xing,
Wang ChuanZeng,
Rahman Shofiur,
Alodhayb Abdullah,
Georghiou Paris E.,
Matsumoto Taisuke,
Tanaka Junji,
Redshaw Carl,
Yamato Takehiko
Publication year - 2020
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201903048
Subject(s) - alkylation , chemistry , lewis acids and bases , medicinal chemistry , conformational isomerism , derivative (finance) , coupling reaction , catalysis , organic chemistry , molecule , financial economics , economics
Anti ‐8‐methoxy[2.2]metacyclophanes (MCPs) 5 a – b were obtained via pyrolysis of the corresponding syn ‐thiatetraoxide cyclophanes 4 a – b . Coupling reactions of 4‐ tert ‐butyl‐1‐methoxy‐2,6‐bis(mercaptomethyl)benzenes 1 a – b and 1,5‐bis(chloro‐methyl)‐2,4‐dimethylbenzene 2 under high dilution conditions afforded only the syn ‐conformers of 9‐methoxy‐2,11‐dithia[3.3]metacyclophanes 3 a – b , which with m ‐CPBA formed the corresponding syn ‐tetraoxides 4 a – b . Lewis acid (TICl 4 /AlCl 3 ‐MeNO 2 ) or iodine‐catalyzed reactions of 5 b under various conditions led to transannular cyclization to afford tetrahydropyrene 6 b and pyrene derivative 7 b and/or de‐ tert ‐butylated 6 a . Iodine‐catalyzed reaction of 5 a afforded tetrahydropyrene 6 a . These findings suggest the potential for a new route to alkylated pyrenes via strained and alkylated metacyclophanes. Density functional theory (DFT) studies were carried out to investigate the conformational characteristics of 3–5 .