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Continuous‐Flow Oxidative Cyanation of Primary and Secondary Amines Using Singlet Oxygen
Author(s) -
Ushakov Dmitry B.,
Gilmore Kerry,
Kopetzki Daniel,
McQuade D. Tyler,
Seeberger Peter H.
Publication year - 2014
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201307778
Subject(s) - strecker amino acid synthesis , chemistry , trimethylsilyl cyanide , primary (astronomy) , cyanation , singlet oxygen , oxidative coupling of methane , imine , tetraphenylporphyrin , amine gas treating , cyanide , oxidative phosphorylation , oxygen , catalysis , photochemistry , organic chemistry , porphyrin , biochemistry , physics , astronomy , enantioselective synthesis
Abstract Primary and secondary amines can be rapidly and quantitatively oxidized to the corresponding imines by singlet oxygen. This reactive form of oxygen was produced using a variable‐temperature continuous‐flow LED‐photoreactor with a catalytic amount of tetraphenylporphyrin as the sensitizer. α‐Aminonitriles were obtained in good to excellent yields when trimethylsilyl cyanide served as an in situ imine trap. At 25°C, primary amines were found to undergo oxidative coupling prior to cyanide addition and yielded secondary α‐aminonitriles. Primary α‐aminonitriles were synthesized from the corresponding primary amines for the first time, by an oxidative Strecker reaction at –50 °C. This atom‐economic and protecting‐group‐free pathway provides a route to racemic amino acids, which was exemplified by the synthesis of tert ‐leucine hydrochloride from neopentylamine.