Triflic Acid Mediated Cascade Cyclization of Aryldiynes for the Synthesis of Indeno[1,2‐c]chromenes: Application to Dye‐Sensitized Solar Cells

Abstract

A new triflic acid (TfOH)-mediated cascade cyclization of ortho-anisole-substituted aryldiynes is described for the construction of indeno[1,2-c]chromenes. The cascade cyclization proceeds through an unusual TfOH-induced alkyne-alkyne cyclization followed by nucleophilic attack of the methoxy group on the benzylidene cation, which is completely different to the cyclization of ortho-aniline- or ortho-thioanisole-substituted aryldiynes. A new class of organic dyes with the indeno[1,2-c]chromene framework as both donor and π-linker were synthesized. These compounds exhibit high photovoltaic performances in dye- sensitized solar cells (DSCs).

Selenocystine Peptides Performance in 5‐endo‐dig Reactions

“…We chose to utilize anisole‐containing aryldiyne 7 for the construction of indeno[1,2‐ c ]chromene skeleton. Chromene moiety is often found in biologically active natural products, furthermore, compounds containing indeno[1,2‐ c ]chromene core show high potential for use in dye‐sensitized photovoltaic cells , . Notably, only few methods exist for the construction of indeno[1,2‐ c ]chromene moiety.…”

“…Notably, only few methods exist for the construction of indeno[1,2‐ c ]chromene moiety. Previously, TfOH mediated cascade reaction of anisole 7 has been performed for the synthesis of 6‐phenylindeno[1,2‐ c ]chromene, while halogen‐mediated cascade reaction has been reported by Chen et al for the synthesis of halogenated 6‐phenylindeno[1,2‐ c ]chromenes …”

“…Boc‐ l ‐selenocystine, peptides 3a , b , c , 2‐(1‐alkynyl)anisoles 1a , b , 2‐(1‐alkynyl)phenols 1c , d , 2‐(1‐alkynyl)anilines 5a–c , f , g , h , i , j , and 7 were prepared according to literature procedures.…”

π-Conjugated carbocycles and heterocycles via annulation through C-H and X-Y activation across CC triple bonds

“…However, in the case of anisoles 40 (Y=O in Scheme 8), iodine-mediated and -electrophilic transition metal-catalyzed cyclization did not give the desired -conjugated product (Scheme 13). 103 Instead, use of 2 equivalents of TfOH in CH 3 CN afforded the indenochromene -conjugated system 41 in a very high yield.…”

ZnBr2-Mediated Cascade Reaction of o-Alkoxy Alkynols: Synthesis of Indeno[1,2-c]chromenes

“…Indenochromenes are one of the privileged classes of O -heterocycles because of their presence in natural products with versatile biological properties. ,, Indeno­[1,2- c ]­chromene is a precursor of gnetuhainin S (Figure A), which was isolated from Gnetum macrostachyum lianas and displays potent antioxidant activity as a radical scavenger against DPPH. , Parvifolols A–C exhibit strong inhibitory activity against the Maillard reaction (Figure B–D) . In addition, they have been used in the synthesis of new organic JH dyes (donor−π-linker–acceptor dyes) as a new donor moiety as well as a π-linker for use in high-performance dye-sensitized solar cells …”