2-(1,3-Dioxan-2-yl)ethylsulfonyl Group:  A New Versatile Protecting and Activating Group for Amine Synthesis

Abstract

[reaction: see text] 2-(1,3-Dioxan-2-yl)ethylsulfonyl (Dios) chloride was synthesized and used as a new versatile sulfonating agent for amines. Primary and secondary amines were sulfonated very easily in excellent yields with Dios chloride. N-Nonsubstituted and N-monosubstituted Dios-amides, activated amines, were alkylated satisfactorily under new Mitsunobu conditions utilizing (cyanomethylene)tributylphosphorane (CMBP). The Dios group is very stable under basic and reductive conditions and is removed by heating in a hot aqueous solution of trifluoroacetic acid.

Mild Electrochemical Deprotection of N‐Phenylsulfonyl N‐Substituted Amines Derived from (R)‐Phenylglycinol

“…Pyridylsulfonyl chloride is, however, still not commercially available and its preparation is not straightforward 15. Other sulfonyl protecting groups that have also been reported are the (β‐trimethylsilyl)ethanesulfonyl (SES)16,17 and the 2‐(1,3‐dioxan‐2‐yl)ethylsulfonyl (Dios)18 or heteroarenesulfonyl groups;19,20 they are, however, not commercially available. Recently, a new sulfonamide analogue of the Boc group, the tert ‐butylsulfonyl group (Bus), which is stable to strong metallation conditions, was introduced 21.…”

Direct substitution of the hydroxy group with highly functionalized nitrogen nucleophiles catalyzed by Au(iii)

“…In particular, there is almost no access to more useful but acid-sensitive nucleophiles such as tert-butyl carbamate. 8b,10e,12a Here, we report that direct substitutions of allylic and benzylic alcohols with synthetically useful tert-butoxycarbonyl (Boc), thiophenesulfonyl, 17 tertbutylsulfonyl (Bus), 18 and 2-(1,3-dioxan-2-yl)ethylsulfonyl (Dios) 19 protected amine nucleophiles are efficiently catalyzed by 1 mol% of NaAuCl 4 •2H 2 O under mild conditions (rt to 40 ˚C). Reactions with more acid-sensitive functional groups such as TBS and THP groups were achieved using dichloro(pyridine-2carbozylato)gold (III) (4) 20 as a catalyst.…”

“…The reaction with Cbz-amide 2m afforded the corresponding product 3am in 94% yield (Entry 14). Synthetically useful thiophenesulfonyl (Entry 15), 17 Bus (Entry 16), 18 and Dios (Entry 17) 19 amides, which are readily deprotected by Mg, TFA with anisole, and aq. TFA, respectively, to give the corresponding amines, were first utilized in the direct catalytic amination reaction.…”

Transition-Metal-Free and Visible-Light-Mediated Desulfonylation and Dehalogenation Reactions: Hantzsch Ester Anion as Electron and Hydrogen Atom Donor

“…The cleavage of N–S bond can be acid-mediated by HBr, − HCl, H 2 SO 4 , , CF 3 COOH, CF 3 SO 3 H, HF-pyridine with anisole, or CH 3 COOH/HClO 4 mostly under very harsh conditions or at high temperatures. Moreover, the N-deprotection method using HBr requires a bromine scavenger such as phenol to avoid monobromination and/or dibromination of the aromatic ring of aniline.…”