Development of fluorination methods using continuous-flow microreactors
作者:Marcus Baumann、Ian R. Baxendale、Laetitia J. Martin、Steven V. Ley
DOI:10.1016/j.tet.2009.05.083
日期:2009.8
The safe and reliable use of various fluorination methods including nucleophilic fluorination (DAST), trifluoromethylation (Ruppert's reagent) and electrophilic fluorination (Selectfluor®) in a continuous-flow microreactor is reported. Special attention was given to the use of in-line scavenging procedures in order to obtain clean products without the need for further purification.
There is provided a novel, useful dehydroxyfluorination agent containing sulfuryl fluoride (SO
2
F
2
) and an organic base that is free from a free hydroxyl group in the molecule. According to the present dehydroxyfluorination agent, it is not necessary to use perfluoroalkanesulfonyl fluoride, which is not preferable in large-scale use, and it is possible to advantageously produce optically-active fluoro derivatives, which are important intermediates of medicines, agricultural chemicals and optical materials, for example, 4-fluoroproline derivatives, 2′-deoxy-2′-fluorouridine derivatives, optically-active α-fluorocarboxylate derivatives, and monofluoromethyl derivatives, even in large scale.
It was found that a fluoro derivative can be produced by reacting a hydroxy derivative with sulfuryl fluoride (SO
2
F
2
) in the presence of an organic base or in the presence of an organic base and “a salt or complex comprising an organic base and hydrogen fluoride”. According to the present production process, it is not necessary to use perfluoroalkanesulfonyl fluoride, which is not preferable in industrial use, and it is possible to advantageously produce optically-active fluoro derivatives, which are important intermediates of medicines, agricultural chemicals and optical materials, specifically 4-fluoroproline derivatives, 2′-deoxy-2′-fluorouridine derivatives, optically-active α-fluorocarboxylate derivatives, and the like, even in a large scale.
There is provided a novel, useful dehydroxyfluorination agent containing sulfuryl fluoride (SO2F2) and an organic base that is free from a free hydroxyl group in the molecule. According to the present dehydroxyfluorination agent, it is not necessary to use perfluoroalkanesulfonyl fluoride, which is not preferable in large-scale use, and it is possible to advantageously produce optically-active fluoro derivatives, which are important intermediates of medicines, agricultural chemicals and optical materials, for example, 4-fluoroproline derivatives, 2'-deoxy-2'-fluorouridine derivatives, optically-active α-fluorocarboxylate derivatives, and monofluoromethyl derivatives, even in large scale.