69001-12-3Relevant articles and documents
Memory of Chirality in Flow Electrochemistry: Fast Optimisation with DoE and Online 2D-HPLC
Ahmed, Nisar,Cicala, Rossana,Hardwick, Tomas,Santi, Micol,Seitz, Jakob,Wirth, Thomas
supporting information, p. 16230 - 16235 (2019/11/28)
Amino acid derivatives undergo non-Kolbe electrolysis to afford enantiomerically enriched α-alkoxyamino derivatives through intermediate chiral carbenium ions. The products contain N,O-acetals which are important structural motifs found in bioactive natural products. The reaction is performed in a continuous flow electrochemical reactor coupled to a 2D-HPLC for immediate online analysis. This allowed a fast screening of temperature, electrode material, current, flow-rate and concentration in a DoE approach. The combination with online HPLC demonstrates that also stereoselective reactions can benefit from a hugely accelerated optimisation by combining flow electrochemistry with multidimensional analysis.
Electrochemical deallylation of α-allyl cyclic amines and synthesis of optically active quaternary cyclic amino acids
Kirira, Peter G.,Kuriyama, Masami,Onomura, Osamu
experimental part, p. 3970 - 3982 (2010/07/04)
Electrochemical oxidation of α-allylated and α-betizylated N-acylated cyclic amines by using a graphite anode easily affords the corresponding α-methoxylated products with up to 76% yield. Ease of oxidation was affected by the type of electrode, the size
Exploratory synthetic studies of the α-methoxylation of amides via cuprous ion-promoted decomposition of o-diazobenzamides
Han, Gyoonhee,LaPorte, Matthew G.,McIntosh, Mathias C.,Weinreb, Steven M.,Parvez, Masood
, p. 9483 - 9493 (2007/10/03)
A convenient nonelectrochemical amide oxidation method has been developed. The process involves a cuprous ion-promoted decomposition of o-diazobenzamides like 4, generated in situ from the corresponding o-aminobenzamides, to give N-acyliminium ion intermediate 9 via a 1,5-H-atom transfer, followed by metal-catalyzed oxidation of the resulting α-amidyl radical. The transformation produces α-methoxybenzamides 15 in good yields. An attempt was made to apply this oxidation method to a total synthesis of the alkaloid (-)-anisomycin (16). Scalemic o-aminobenzamide pyrrolidine derivatives 18a/18b underwent oxidation to give α-methoxylated amide substrates 19a/19b, respectively, in good yields. However, alkylation of the N-acyliminium intermediate 20 with (p-methoxybenzyl)magnesium chloride gave the undesired anti-compounds 22a/22b as the major products. The amide oxidation exhibits good regioselectivity with many unsymmetrical 2-substituted piperidine and pyrrolidine systems. In general, it appears that the larger the C-2 substituent, the greater the methylene/methine H-atom abstraction ratio. A mechanistic rationale for this selectivity is suggested based upon amide rotamer populations. An extension of this methodology can be used to conduct two sequential amide oxidations using readily prepared 2-amino-6-nitrobenzamides such as 68 and 69.
