An easy-to-handle sodium dispersion in paraffin oil (SD), in combination with inexpensive and environmentally benign 1,3-dimethyl-2-imidazolidinone (DMI) as an additive enables the Birch-type reduction of a variety of arenes with high yields, selectivity, and tolerance of functionality such as ether, alcohol, amine, amide, and carboxylic acid.
Phenylalanine – a biogenic ligand with flexible η6- and η6:κ1-coordination at ruthenium(ii) centres
作者:Thomas Reiner、Dominik Jantke、Xiao-He Miao、Alexander N. Marziale、Florian J. Kiefer、Jörg Eppinger
DOI:10.1039/c3dt50589h
日期:——
The reaction of (S)-2,5-dihydrophenylalanine 1 with ruthenium(III) chloride yields the μ-chloro-bridged dimeric η6-phenylalanine ethyl ester complex 3, which can be converted into the monomeric analogue, η6:κ1-phenylalanine ethyl ester complex 12, under basic conditions. Studies were carried out to determine the stability and reactivity of complexes bearing η6- and η6:κ1-chelating phenylalanine ligands under various conditions. Reaction of 3 with ethylenediamine derivatives N-p-tosylethylenediamine or 1,4-di-N-p-tosylethylenediamine results in the formation of monomeric η6:κ1-phenylalanine ethyl ester complexes 14 and 15, which could be saponified yielding complexes 16 and 17 without changing the inner coordination sphere of the metal centre. The structure of η6:κ1-phenylalanine complex 17 and an N-κ1-phenylalanine complex 13 resulting from the reaction of 3 with an excess of pyridine were confirmed by X-ray crystallography.
Mechanochemical Approach for Air‐Tolerant and Extremely Fast Lithium‐Based Birch Reductions in Minutes
作者:Yunpeng Gao、Koji Kubota、Hajime Ito
DOI:10.1002/anie.202217723
日期:——
mechanochemical Birchreduction is reported for the first time. The newly developed ball-milling method does not require an inert atmosphere or other special precautions. Notably, the reaction completed within one minute for most of the investigated substrates. The present study thus provides a novel, operationally simple, rapid, and scalable alternative to conventional solution-based Birchreduction.