One‐Pot Ring‐Closing Metathesis/1,3‐Dipolar Cycloaddition through Assisted Tandem Ruthenium Catalysis: Synthesis of a Dye with Isoindolo[2,1‐a]quinoline Structure

Abstract

Assisted tandem catalytic reactions are defined as catalyzed reaction sequences that proceed through more than one mechanism, but with just one precatalyst. [1] In these reactions, the catalyst of the first cycle is transformed into the catalyst of the second cycle by a chemical initiator, for example, an additive that induces an organometallic transformation in situ. Over the past decade, several reaction sequences comprising an olefin-metathesis step and a subsequent nonmetathesis [2] transformation of the newly generated carbon= carbon bond were developed. For example, olefin metathesis can be combined with hydrogenation [3] or isomerization [4] by in situ conversion of a Ru-carbene into a Ru-hydride. [5] Ruthenium-alkylidene-catalyzed tandem transformations that were developed to date include olefin metathesis, followed by cyclopropanation, [6] hydrovinylation, [7] hydroarylation, [8] the aza-Michael reaction, [9] the hetero-Pauson-Khand reaction, [10] or oxidation. [11] On the other hand, [RuClCp*] and the "first generation" Grubbs metathesis complex A (Figure 1) catalyze an azidealkyne cycloaddition reaction to give 1,5-substituted triazoles, [12] and an intramolecular [3+2] cycloaddition of alk-5ynylidenecyclopropanes to give bicyclo[3.3.0]octane, [13] respectively.In our search for novel and efficient Ru-catalyzed reactions, [2c, 3, 11d, 14] we developed a one-pot ring-closing metathesis/oxidation methodology to produce various 2-quinolones from N-allyl-2-vinylaniline derivatives (Scheme 1). [11d] Oxidation of the a-methylene group of amines to the corresponding amides is very difficult. [15] The key intermedi-

Metal-Free Nitrogen-Containing Polyheterocyclic Near-Infrared (NIR) Absorption Dyes: Synthesis, Absorption Properties, and Theoretical Calculation of Substituted 5-Methylisoindolo[2,1-a]quinolines

“…In addition, we calculated all the above compounds 3a , 3d–h , 3j , 3l , 3m, and 3p (Figure 7) 13 in order to understand a structure and an absorption–wavelength relationships using time-dependent density functional theory (TD-DFT). All calculations were performed using Gaussian 09 (Rev.…”

“…To a solution of N -benzyl-2-vinylaniline 13 (88.0 mg, 0.598 mmol) in DMF (1.2 mL) was added 3-chloro-2-methyl-1-propene (117 μL, 1.20 mmol), K 2 CO 3 (207 mg, 1.50 mmol) and TBAI (221 mg, 0.598 mmol) and the whole was stirred at 120 °C overnight. After the reaction mixture was cooled to rt, to the reaction mixture was added sat.…”

“…In our search for a novel and efficient ruthenium-catalyzed one-pot reaction involving both metathesis and nonmetathesis reactions, 11,12 we previously developed a one-pot ring-closing metathesis (RCM)/oxidation/1,3-dipolar cycloaddition protocol to prepare various isoindolo[2,1- a ]quinolines 3 from N -allyl-2-alkenylaniline derivatives 1 (Scheme 1). 13 The key intermediate in this reaction is likely to be azomethine ylide I derived from 1,2-dihydroquinoline 2 .…”

“…14 For instance, 5,11-dioxoisoindolo[2,1- a ]quinolines are analogs of berberine alkaloids that have been shown to have an inhibitory effect against N 2 -induced hypoxia 14a and inhibit human topoisomerase II. 14b Meanwhile, 7,10-dioxoisoindolo[2,1- a ]quinolines, first synthesized by our group, 13 are functional dyes. In particular, we found that compound 3 showed a variety of colors when exchanging the R 1 substituent (R 1 = Ph, Me), including blue, yellow, and red (Scheme 1 and Figure 3), despite the core structure of 3 being the same as that of the 7,10-dioxoisoindolo[2,1- a ]quinoline system.…”

Development of an Enyne Metathesis/Isomerization/Diels–Alder One‐Pot Reaction for the Synthesis of a Novel Near‐Infrared (NIR) Dye Core

“…In our search for novel and efficient Ru‐catalyzed reactions,8c, 9, 17d, 18 we developed a one‐pot ring‐closing metathesis/oxidation and a one‐pot ring‐closing metathesis/1,3‐dipolar cycloaddition to produce various 2‐quinolones and isoindoloquinolines (Scheme ), respectively, from N ‐allyl‐2‐alkynylaniline derivatives 17d. 18 Considering the importance of streamlining syntheses toward complex molecular targets, we describe herein our novel one‐pot metathesis/nonmetathesis process; that is, a one‐pot enyne metathesis/isomerization/Diels–Alder reaction, to give 7‐methyl‐4 H ‐naphtho[3,2,1‐ de ]quinoline‐8,11‐dione derivatives, which are novel NIR dyes.…”