3661-63-0Relevant academic research and scientific papers
Hydrogen Bonding Networks Enable Br?nsted Acid-Catalyzed Carbonyl-Olefin Metathesis**
Anh To, Tuong,Pei, Chao,Koenigs, Rene M.,Vinh Nguyen, Thanh
, (2022/02/17)
Synthetic chemists have learned to mimic nature in using hydrogen bonds and other weak interactions to dictate the spatial arrangement of reaction substrates and to stabilize transition states to enable highly efficient and selective reactions. The activation of a catalyst molecule itself by hydrogen-bonding networks, in order to enhance its catalytic activity to achieve a desired reaction outcome, is less explored in organic synthesis, despite being a commonly found phenomenon in nature. Herein, we show our investigation into this underexplored area by studying the promotion of carbonyl-olefin metathesis reactions by hydrogen-bonding-assisted Br?nsted acid catalysis, using hexafluoroisopropanol (HFIP) solvent in combination with para-toluenesulfonic acid (pTSA). Our experimental and computational mechanistic studies reveal not only an interesting role of HFIP solvent in assisting pTSA Br?nsted acid catalyst, but also insightful knowledge about the current limitations of the carbonyl-olefin metathesis reaction.
Dissymmetric ansa zirconocene complexes with di- and trisubstituted indenyl ligands as catalysts for homogeneous ethylene homo- and ethylene/1-hexene copolymerization reactions
Rimkus, Andrea M.,Alt, Helmut G.
, p. 72 - 82 (2017/02/18)
Different routes for the synthesis of 1,2- and 1,2,3-substituted indene derivatives are described. Representative substituents are: Me, Ph, PhCH2, PhCH2CH2, PhCH2CH2CH2, CH2CH?=?CH2. Subsequent deprotonation of these substituted indenes and reaction with indenyl zirconium trichloride gave the corresponding dissymmetric bis(indenyl) zirconium complexes. After activation with methylaluminoxane (MAO) these complexes show high activities both in ethylene homopolymerisation and ethylene/1-hexene copolymerisation. The rate of comonomer incorporation can reach 33.3% (15/MAO). The copolymers exhibit lower melting points than the homopolymers and their crystallinities α are lower compared with the homopolymers.
Gold(I)-catalyzed cyclodehydration enabled by the triisopropylsilyl group: A synthetically versatile methodology
Usanov, Dmitry L.,Naodovic, Marina,Brasholz, Malte,Yamamoto, Hisashi
, p. 1773 - 1789,17 (2012/12/12)
Introduction of a triisopropylsilyl group into allyl and allenyl carbinols greatly enhances the efficiency of gold(I)-catalyzed cyclodehydration, which can provide rapid access to a library of various compounds including 1H-indenes (Table 2 and Scheme 5), benzofulvenes (Table 3), indan-2-ones (Scheme 2), fulvenes (Table 4), cyclopentadienes (Table 4), 5H-dibenzo[a,c][7]annulenes (Scheme 6) and dibenzosuberones (Scheme 6). The developed method enables unprecedented product generality for several classes of cyclodehydration reactions, which is particularly notable for the preparation of 1H-indenes. The first synthesis of non-benzo-fused fulvenes via cyclodehydration of allenyl vinyl carbinols could be accomplished. The protocol is remarkable for mild conditions, operational convenience, and easy access to starting materials. Copyright
Formation of five- and seven-membered rings enabled by the triisopropylsilyl auxiliary group
Usanov, Dmitry L.,Yamamoto, Hisashi
supporting information; experimental part, p. 414 - 417 (2012/02/15)
A highly convenient synthetic pathway to 2-indanones from aldehydes was established. The introduction of a triisopropylsilyl group greatly facilitated Meinwald rearrangement of the intermediate epoxides and alleviated the necessity of polysubstitution for the clean formation of indenes and cyclopentadienes via cyclodehydration of allylic alcohols; unprecedented freedom with respect to the product structure was thus achieved. The developed methodology could also be applicable to the formation of seven-membered rings leading to dibenzo[7]annulenes and dibenzosuberones.
Low-valent niobium-mediated synthesis of indenes: Intramolecular coupling reaction of CF3 group with alkene C-H bond
Fuchibe, Kohei,Mitomi, Ken,Akiyama, Takahiko
, p. 24 - 25 (2007/10/03)
CF3 group of o-alkenyl-α,α,α-trifluorotoluenes underwent intramolecular coupling reaction with the alkene C-H bond under NbCl5/LiAlH4 system. Substituted indenes were obtained in good yields. Copyright
Ozonolysis of a Series of 1-Substituted Indenes. The Substituent Steric Effects on Ozonide Exo/Endo Ratios
Miura, Masahiro,Nojima, Masatomo,Kusabayashi, Shigekazu,McCullough, Kevin J.
, p. 2932 - 2936 (2007/10/02)
The ozonolysis of a series of disubstituted (1,2 and 1,3) and trisubstituted (1,2,3) indenes 1-28 in carbon tetrachloride at 20 deg C has been investigated.The major product in each case was the corresponding bicyclic ozonide, usually obtained as a mixtur
Sigmatropic Indenyl Rearrangements Induced by Electronic Excitation
Padwa, Albert,Goldstein, Steven,Loza, Roman,Pulwer, Mitchell
, p. 1858 - 1868 (2007/10/02)
The photochemical rearrangement of several arylalkyl substituted indenes has been studied.The rearrangements were shown to be derived from the ?,?* singlet state since triplet sensitization led to no reaction or else resulted in a Paterno-Buchi
