Issue 3, 2018

Metal-free remote-site C–H alkenylation: regio- and diastereoselective synthesis of solvatochromic dyes

Abstract

Lately, transition-metal catalysed C–H alkenylation of nitrogen heterocycles has gained increasing attention, often with the intervention of complex and expensive catalytic systems. On the other hand, both, chalcones and indolizines are versatile families of compounds with applications in diverse research areas, including materials science, because of their prominent photophysical attributes. We set forth herein the metal-free regio- and diastereoselective C–H alkenylation of indolizines through a very simple and mild acid–base approach. The most fascinating fact in this remote-site Csp2–Csp2 bond formation is that only one starting material is utilised, which undergoes a formal self-alkenylation to integrate a chalcone moiety and furnish a new family of dyes; a plausible reaction mechanism has been put forward. A one-pot multicomponent protocol was conceived that generates the starting indolizine in situ and has been extended to a multi-gram scale synthesis with equal efficiency. The dyes show a single structure in the solid state but two stable structures in solution (rotamers). Preliminary studies on the optical properties of the dyes reveal a particle-size dependent colour in the solid state and solvatochromism (i.e., different colours in solution depending on the solvent polarity). Remarkably, the solvatochromic behaviour was also displayed in plastics. We believe that this finding opens new avenues in the fields of heterocyclic chemistry, dyes, and materials science.

Graphical abstract: Metal-free remote-site C–H alkenylation: regio- and diastereoselective synthesis of solvatochromic dyes

Supplementary files

Article information

Article type
Paper
Submitted
14 Nov 2017
Accepted
18 Dec 2017
First published
27 Dec 2017

Green Chem., 2018,20, 701-712

Metal-free remote-site C–H alkenylation: regio- and diastereoselective synthesis of solvatochromic dyes

M. J. Albaladejo, M. J. González-Soria and F. Alonso, Green Chem., 2018, 20, 701 DOI: 10.1039/C7GC03436A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements