Studies in organic and physical photochemistry - an interdisciplinary approach.

Michael Oelgemöller,Norbert Hoffmann

doi:10.1039/c6ob00842a

Abstract

Traditionally, organic photochemistry when applied to synthesis strongly interacts with physical chemistry. The aim of this review is to illustrate this very fruitful interdisciplinary approach and cooperation. A profound understanding of the photochemical reactivity and reaction mechanisms is particularly helpful for optimization and application of these reactions. Some typical reactions and particular aspects are reported such as the Norrish-Type II reaction and the Yang cyclization and related transformations, the [2 + 2] photocycloadditions, particularly the Paternò-Büchi reaction, photochemical electron transfer induced transformations, different kinds of catalytic reactions such as photoredox catalysis for organic synthesis and photooxygenation are discussed. Particular aspects such as the structure and reactivity of aryl cations, photochemical reactions in the crystalline state, chiral memory, different mechanisms of hydrogen transfer in photochemical reactions or fundamental aspects of stereoselectivity are discussed. Photochemical reactions are also investigated in the context of chemical engineering. Particularly, continuous flow reactors are of interest. Novel reactor systems are developed and modeling of photochemical transformations and different reactors play a key role in such studies. This research domain builds a bridge between fundamental studies of organic photochemical reactions and their industrial application.

Highlights

When compared to reactions at the ground state, photochemical transformations are characterized by the fact that they involve electronic excitation.[1]
Since the reactivity of a chemical compound is defined by its electron configuration, it is obvious that the photochemical reaction conditions considerably augment the number of transformations of a compound family
The traditionally strong links between organic photochemistry and physical chemistry enable a high level of understanding of these reactions.[1,2,4]

Summary

Introduction

When compared to reactions at the ground state, photochemical transformations are characterized by the fact that they involve electronic excitation.[1] by light absorption the electron configuration of a molecule changes. Since the reactivity of a chemical compound is defined by its electron configuration, it is obvious that the photochemical reaction conditions considerably augment the number of transformations of a compound family. Photochemical reactivity is even complementary to ground state chemistry. This phenomenon may be described by potential-energy surface topology.[2,3] Applying photochemical methods to organic synthesis, products can be synthesized which are difficultly or not available with conventional methods.[4,5] Many catalytic reactions with organometallic compounds or enzymes are improved under these conditions. Since photochemical reactions can be performed under mild conditions, they further enable studying transformations in supramolecular structures or investigating particular phenomena of absolute

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