Diarylethenes microflow system

Following similar trials with the formation of diarylbenzenes [63-65], the same research group has reported a multistep synthesis of photochromic diarylethenes using a microflow system that contained two linked micromixers and microreactors (MRi 2) [66]. Similarly to the previously reported linked microreactors, the reactors used in this setup were made of stainless steel tubes and T-shaped micromixers. Initial experiments were conducted in two steps in a continuous sequence to afford symmetrical octasubstitued diaryUiexafluoro cyclopentene (Scheme 29). 

Scheme 30 Synthesis of an unsymmetrical diarylethene using a multistep microflow system [66]...

Ushiogi Y, Hase T, linuma Y et al (2007) Synthesis of photochromic diarylethenes using a microflow system. Chem Commun 28 2947-2949... 

The synthesis of diarylethenes from hetaryl bromides and octafluoro-cyclopentene using a microflow system allows the preparation of various symmetrical and unsymmetrical diarylperfluorocyclopentenes in 47-87% yields at 0°C (07CC2947). 

Using a stainless-steel microreactor, Ushiogi et al. (2007) reported a microflow system capable of synthesizing unsymmetrical diarylethenes, a process that is notoriously difficult to achieve in conventional batch systems. As Scheme 62 illustrates, diarylethenes are of synthetic interest due to their ability to change color via a reversible switching between two distinct isomers, which occurs as a result of light absorption. 

Figure 10.4 Synthesis of unsymmetrical diarylethenes in a microflow system...

---