N-Chloro-N-sodio-carbamates as a Practical Amidating Reagent for Scalable and Sustainable Amidation of Aldehydes under Visible Light

Abstract

Herein, we describe the scalability and sustainability investigations toward the visible light-mediated amidation of aldehydes with N-chloro-N-sodio-carbamates. The practicality credentials of N-chloro-N-sodio-carbamates for their use in multigram scale amidation reactions are proven by scale-up productions and thermogravimetric analysis. The described amidation, which was previously hampered in sustainability perspectives by the use of α,α,α-trifluorotoluene solvent, is now improved through re-optimizations using ethyl acetate as an alternative green solvent. The generality of multigram scale amidations is demonstrated by the conversion of a selected list of aldehydes, in which the corresponding amides can be isolated in high purity without the need for special purification procedures.

One‐Pot Conversion of Benzyl Alcohols to N‐Protected Anilines and Alkyl Alcohols to Carbamoyl Azides

“…In these scalable processes, the conversion of aldehydes to acid chlorides is facilitated by LED light and does not require photo‐responsive additives. The simplicity of the reaction system agrees with recent photocatalyst‐free, light‐assisted reports [13,29] . Additionally, our one‐pot procedures were found to be more efficient than stepwise or semi‐stepwise procedures.…”

“…The simplicity of the reaction system agrees with recent photocatalyst-free, light-assisted reports. [13,29] Additionally, our one-pot procedures were found to be more efficient than stepwise or semi-stepwise procedures. This is notable for one-pot, multi-step reaction sequences that are not intramolecular.…”

A practical method for the aziridination of α,β-unsaturated carbonyl compounds with a simple carbamate utilizing sodium hypochlorite pentahydrate

“… 11 As a simple carbamate, we focused on tert -butyl carbamate because it contains a Boc group that can be readily removed. In fact, when tert -butyl carbamate was treated with NaOCl·5H 2 O in MeCN at room temperature for 3 h, tert -butyl N -chloro- N -sodio-carbamate (chloramine-Boc) 12 was obtained in high yield ( Scheme 2 ).…”

Green and sustainable visible light-mediated formation of amide bonds: an emerging niche in organic chemistry

“…Very recently, Chang and co-workers developed a visible light-driven photocatalyst-free amidation of aldehydes 1 by utilizing N -chloro- N -sodio-carbamates 88 as a surrogate of amines (Scheme 40). 102 Under visible light illumination, N -chloro- N -sodio-carbamate 88 reacts with the in situ generated acyl chloride 40C to produce the intermediate 40A , which undergoes an N–Cl bond fragmentation to yield the N -centered radical species 40B . Lastly, a HAT from aldehyde 1 by the intermediate 40B gives the desired product 89 with the regeneration of acyl chloride 40C .…”