Seasoning Materials Chemistry by Using a Well‐Matured Organic Concept

Abstract

The concept "introduction of allylic 1,3-strain (A(1,3)-strain) to photochromism" originated from the experience of total synthesis of natural products about 18 years ago, when the author was a post doc. It was first applied to synthetic organic reactions, then it was successfully employed in the diastereoselective photochromic reactions of diarylethenes. A diastereomeric excess of the photoreaction was 88 % for the first example, and it was improved to 94 % by the recent operation of rational molecular tailoring.

Photochromism of Diarylethene Molecules and Crystals: Memories, Switches, and Actuators

“…Yokoyama et al , adopted allylic 1,3-strain as a tool , to achieve highly diastereoselective photocyclizations of diaryl­ethenes. The concept of allylic stain is shown in Scheme .…”

A Unified Strategy for Exceptionally High Diastereoselectivity in the Photochemical Ring Closure of Chiral Diarylethenes

“…Diastereoselective ring closure of diarylethenes through photochemical reactions, which can be achieved for molecules possessing at least one chirality unit, have been reported in solution,14 crystals,15 amorphous solids,16 and gels 17. We have also developed the diastereoselective ring closure of photochromic diarylethenes in solution by applying the concept of the allylic 1,3‐strain18–21 to the hexatriene moiety, which gave 88–94 % diastereomeric excess ( de ) by using only one chiral unit to control the stereochemistry 22–25. Herein, we report on a photochromic system that undergoes a highly diastereoselective ring closure with up to 100 % de .…”

Indium-Catalyzed Regioselective β-Alkylation of Pyrroles with Carbonyl Compounds and Hydrosilanes and Its Application to Construction of a Quaternary Carbon Center with a β-Pyrrolyl Group

“…Although there may be a possibility to afford another cationic species α-11 from same intermediate α,β′-5 , the selective formation of β-11 thus leading to β-4 is likely to be due, at least in part, to two synergistic effects. One is the higher stability of β-11 itself compared to the corresponding α-11 that has the higher 1,3-allylic-type strain between R 1 (≠ H) and R 2 (Scheme , (ii)) . The other is the higher leaving group character of the α-pyrrolyl group than the β-pyrrolyl group (see Scheme , (v)), and this experimental fact should thus be attributed to the higher stability of α-pyrrolylindium α-10 than β-pyrrolylindium β-10 (Scheme , (iii)) because, in general, an α-pyrrolylmetal, which means an α-pyrrolylanion, is relatively more stable .…”