More sustainable use of chemical resources is part of the United Nations 2030 Agenda. Therefore, synthetic chemists work to design and carry out efficient syntheses. Within the arsenal of synthetic organic chemistry, the processes that bind several molecules (coupling partners) in a single step – the so-called multicomponent reactions (MCR) – play a central role. Sustainable and environmentally friendly technologies are considered for the rapid production of complex structures and drugs in a single reaction step. A team of researchers led by Professor of Chemistry Frank Glorius (University of Münster, Germany) and Dr. Huan-Ming Huang (University of Münster and ShanghaiTech University, China) has for the first time managed to use the so-called cetyl radicals for a novel. MCR. This study was published in the newly founded journal Nature Synthesis.
“Cetyl radicals are very important species in synthetic chemistry. They are often used in the synthesis of complex natural products. However, catalytic chemical transformations using cetyl radicals remain difficult. Their formation often requires” harsh “reaction conditions. “Radicals can also be non-selective in their reaction pathways, which means they are difficult to control,” said Huan-Ming Huang.
The research team used visible light-excited cetyl and palladium catalysis radicals to create an MCR between several coupling partners. In selecting the coupling partners (aldehydes, 1,3-dienes and various nucleophiles), the researchers considered several aspects: Which substances are needed for the reaction to occur, which are readily available, and which products are they useful
“We have been able to tame ketyl-type radicals by combining visible light with small amounts of a commercially available palladium catalyst,” said co-author Peter Bellotti. “This operationally simple, redox-neutral and therefore environmentally friendly approach could become a general platform for the construction of so-called complex motifs of homoallyl alcohol, a structural motif frequently used in chemistry. The one-step synthesis of key intermediates that can be further converted into valuable products is a testament to the versatility of this approach. “
In addition to the synthetic capabilities of this method, the team investigated mechanical complexities using a combined experimental mechanical analysis and functional density theory (DFT) calculations. “We anticipate that the combination of visible light with transition metals such as palladium could inspire more unforeseen synthetic transformations beyond established catalyzed reactions,” sums up Frank Glorius.