SO₂F₂‐Activated Efficient Beckmann Rearrangement of Ketoximes for Accessing Amides and Lactams

Abstract

A novel, mild and practical protocol for the efficient activation of the Beckmann rearrangement utilizing the readily available and economical sulfuryl fluoride (SO 2 F 2 gas) has been developed. The substrate scope of the operationally simple methodology has been demonstrated by 37 examples with [a]

Artificial Intelligence for Computer-Aided Synthesis In Flow: Analysis and Selection of Reaction Components

“…The literature provides some additional evidence to this plausibility. Fluorosulfonyl fluoride in combination with triethyl amine has been used as reagent in the Beckman rearrangement of ketoximines (Zhang et al, 2019). While the reported case does not state that it was carried out in flow, there are several examples of acid-catalyzed Beckman rearrangements that have been performed continuously (Curtin et al, 1993;Ko et al, 2000;Botella et al, 2007).…”

Electrophilically Activated Nitroalkanes in Synthesis of 3,4-Dihydroquinozalines

“…Accordingly, 1-(2-nitrophenyl)ethan-1-one oxime was obtained via published procedure [ 38 ] by addition of hydroxylamine hydrochloride (4.45 g, 64.0 mmol) and sodium acetate (6.56 g, 80 mmol) to a solution of 2-nitroacetophenone (6.61 g, 40.0 mmol) in an ethanol and water mixture (4:1, 100 mL). The reaction mixture was boiled at reflux for 2 h (monitored with TLC), and cooled to RT.…”

“…This compound was obtained via transformation of acetophenone into the corresponding oxime and its subsequent reduction with either sodium borohydride in the presence of TiCl 4 in dimethoxyethane (DME) (method A), or with zinc dust in hydrochloric acid (method B). Accordingly, 1-(2-nitrophenyl)ethan-1-one oxime was obtained via published procedure [38] by addition of hydroxylamine hydrochloride (4.45 g, 64.0 mmol) and sodium acetate (6.56 g, 80 mmol) to a solution of 2-nitroacetophenone (6.61 g, 40.0 mmol) in an ethanol and water mixture (4:1, 100 mL). The reaction mixture was boiled at reflux for 2 h (monitored with TLC), and cooled to RT.…”

Sulfuryl Fluoride Promoted Thiocyanation of Alcohols: A Practical Method for Preparing Thiocyanates

“…10l-m Our group recently reported a mild and practical method for efficiently converting aldehydes or aldoximes into the corresponding nitriles that is mediated by SO 2 F 2 and a base in an economical and green manner. 11 Soon afterwards, we also reported the use of SO 2 F 2 and a base as a simple catalyst system for effectively promoting Beckmann rearrangement of ketoximes into amides or lactams 12 and a cascade process for directly converting nitriles into cyanamides through a SO 2 F 2 -activated Tiemann rearrangement. 13 Inspired by our preliminary research results 14 and the unique properties of SO 2 F 2 , we surmised that SO 2 F 2 might similarly be able to react with alcohols to form intermediate sulfonyl esters that should serve as excellent leaving groups.…”