The Schmidt reaction has been an efficient and widely used synthetic approach to amides and nitriles since its discovery in 1923. However, its application often entails the use of volatile, potentially explosive, and highly toxic azide reagents. Here, we report a sequence whereby triflic anhydride and formic and acetic acids activate the bulk chemical nitromethane to serve as a nitrogen donor in place of azides in Schmidt-like reactions. This protocol further expands the substrate scope to alkynes and simple alkyl benzenes for the preparation of amides and nitriles.
Aliphatic alcohols are common and bulk chemicals in organic synthesis. The site-selective functionalization of non-activated aliphatic alcohols is attractive but challenging. Herein, we report a silver-catalyzed δ-selective Csp3-H bond functionalization of abundant and inexpensive aliphatic alcohols. Valuable oximonitrile substituted alcohols are easily obtained by using well-designed sulphonyl reagents under simple and mild conditions. This protocol realizes the challenging δ-selective C–C bond formation of simple alkanols.
Late-stage methylation is a key technology in the development of pharmaceutical compounds. Methyltransferase biocatalysis may provide powerful options to insert methyl groups into complex molecules with high regio-and chemoselectivity. The challenge of a large-scale application of methyltransferases is their dependence on S-adenosylmethionine (SAM) as a stoichiometric, and thus exceedingly expensive co-substrate. As a solution to this problem, we and others have explored the use of methyl halides as reagents for the in situ regeneration of SAM. However, the need to handle volatile electrophiles, such as methyl iodide (MeI), may also hamper applications at scale. As a more practical solution, we have now developed an enzyme-catalyzed process for the regeneration of SAM with methyl toluene sulfonate. Herein, we describe enzymes from the thiopurine methyltransferase family that accept sulfate-and sulfonate-based methyl donors to convert Sadenosylhomocysteine into SAM with efficiencies that rival MeI-based reactions.
Oximes and oxime ethers are privileged
building blocks and can
be conveniently converted to ketones, amines, hydroxylamines, and
nitriles. We describe the catalytic decarboxylation of aliphatic carboxylic
acids to oxime ethers. With AgNO3 as the catalyst, valuable
oxime ethers bearing various substituents could be easily obtained.
The broad substrate scope, easy accessibility of aliphatic carboxylic
acids, and mild reaction conditions make this strategy immediately
applicable to the synthesis, late-stage functionalization, and modification
of biologically active compounds. Experimental studies show the reaction
undergoes a radical process.
An ovel metal-free allylic CÀC s-bond cleavage of simple olefins to give valuable cinnamyl aldehydes is reported. 1,2-Aryl or alkylmigration through allylic C À Cbond cleavage occurs in this transformation, which is assisted by an alkyl azide reagent. This method enables O-atom incorporation into simple unfunctionalized olefins to construct cinnamyl aldehydes.T he reaction features simple hydrocarbon substrates, metal-free conditions,and high regio-and stereoselectivity. Scheme 1. Allylic CÀCbond cleavage.
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