74032-46-5Relevant academic research and scientific papers
Cobalt-catalyzed acylation-reactions of (hetero)arylzinc pivalates with thiopyridyl ester derivatives
Lutter, Ferdinand H.,Grokenberger, Lucie,Hofmayer, Maximilian S.,Knochel, Paul
, p. 8241 - 8245 (2019/09/19)
A cobalt-catalyzed acylation reaction of various primary, secondary and tertiary alkyl, benzyl and (hetero)aryl S-pyridyl thioesters with (hetero)arylzinc pivalates is reported. The thioesters were prepared directly from the corresponding carboxylic acids under mild conditions, thus tolerating sensitive functional groups. Acylations of α-chiral S-pyridyl esters proceeded with very high stereoretention leading to optically enriched α-chiral ketones.
Light-Driven Vitamin B12-Catalysed Generation of Acyl Radicals from 2-S-Pyridyl Thioesters
Ociepa, Micha?,Baka, Oskar,Narodowiec, Jakub,Gryko, Dorota
supporting information, p. 3560 - 3565 (2017/10/24)
Acyl radicals are invaluable intermediates in organic synthesis, however their generation remains challenging. Herein, we present an unprecedented light-driven, cobalt-catalysed method for the generation of acyl radicals from readily available 2-S-pyridyl thioesters. The synthetic potential of this methodology was demonstrated in the Giese-type acylation of activated olefins in the presence of heptamethyl cobyrrinate. This vitamin B12 derivative proved to be the most efficient catalyst in the studied process. The developed method features broad substrate scope (38 examples), good functional group tolerance, and mild reaction conditions. Moreover, it is easily scalable (illustrated on a 20-fold scale-up procedure), enabling its preparative use. Mechanistic studies revealed that the reaction proceeds via a radical pathway with the key steps involving the formation of an acyl-vitamin B12 complex and subsequent photolysis of the Co?C bond. (Figure presented.).
