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Transition‐Metal‐Catalyzed Direct Arylation of Caged Silsesquioxanes: Substrate Scope and Mechanistic Study
Author(s) -
Imoto Hiroaki,
Wada Satoshi,
Yumura Takashi,
Naka Kensuke
Publication year - 2019
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201900126
Subject(s) - chemistry , silsesquioxane , aryl , catalysis , heteroatom , thiophene , steric effects , combinatorial chemistry , substrate (aquarium) , molecule , chemoselectivity , transition metal , polymer chemistry , polymer , organic chemistry , alkyl , oceanography , geology
Caged silsesquioxane (polyhedral oligomeric silsesquioxane: POSS) is an important class of organic‐inorganic hybrid molecules. The electronic properties of POSS have gradually attracted attention from experimental and computational perspectives, while POSS is generally utilized for reinforcement of polymer materials. Practical synthetic routes to access to aryl‐substituted POSS are effective tools for the systematic studies. Recently, we reported Rh‐catalyzed direct arylation of heptaisobutyl‐POSS with electron‐rich aryl iodides. Herein substrates for the Rh‐catalyzed direct arylation were widely examined: electron‐deficient, sterically‐hindered, and heteroatom‐containing aryl halides, and heptaphenyl‐POSS. Pd‐catalyzed direct arylation of POSS was developed as well. Notably, thiophene was introduced by the Pd‐catalyst, whereas the Rh‐system did not work for the substrate. In addition, the reaction mechanism of the Rh‐catalyzed reaction was elucidated by density functional theory calculations.