Chemoselective Reduction of Tertiary Amides by 1,3-Diphenyl­disiloxane (DPDS)

Abstract

A convenient procedure for the chemoselective reduction of tertiary amides at room temperature in the presence of air and moisture using 1,3-diphenyldisiloxane (DPDS) has been developed. The reaction conditions are tolerant of a great number of functional groups including esters, nitriles, secondary amides, carbamates, sulfoxides, sulfones, sulfonyl fluorides, halogens, aryl-nitro groups, and arylamines. The conditions reported are the mildest to date and utilize EtOAc, a preferred solvent given its excellent safety profile and lower environmental impact. The ease of set up and broad chemoselectivity make this method attractive for organic synthesis. These results further demonstrate the utility of DPDS as a selective reducing agent.

Chemoselective Reactions of Functionalized Sulfonyl Halides

“…[167] Other examples include CrO 3 -mediated oxidation of aromatic side chains, [22] MnO 2 -promoted dehydrogenative oxidation of β-aminoethane sulfonyl fluorides to corresponding ethylene derivatives, [168] Upjohn dihydroxylation, [169] sulfide to sulfoxide oxidation with NaIO 4 , [64] and alkylationoxidation sequence. [170] The SO 2 F fragment is also tolerant to various reductive agents, including NaBH 3 CN, [171] NaBH(OAc) 3 , [24,25,57] diphenyl disiloxane, [172] B 2 H 6 and borane complexes, [89,166,173] DIBAL, [57] sodium ditionite, [174] Bu 3 SnH, [175] Zn -HCl,, [176] Zn -HOAc, [157] Fe -HCl, [177] and Pd- [21,25,59,67,76,[177][178][179] or Ni- [180] catalyzed hydrogenation (Scheme 22).…”

“…The SO 2 F fragment is also tolerant to various reductive agents, including NaBH 3 CN, [171] NaBH(OAc) 3 , [24,25,57] diphenyl disiloxane, [172] B 2 H 6 and borane complexes, [89,166,173] DIBAL, [57] sodium ditionite, [174] Bu 3 SnH, [175] Zn – HCl,, [176] Zn – HOAc, [157] Fe – HCl, [177] and Pd‐ [21,25,59,67,76,177–179] or Ni‐ [180] catalyzed hydrogenation (Scheme 22).…”

One-Pot Route from Halogenated Amides to Piperidines and Pyrrolidines

“…The following supporting information can be downloaded at: , 1 H NMR data and spectrum, HMRS data, character for compound 7a – 7u ; 13 C NMR data and spectrum for compound 7u ; structures of the amide substrates. References [ 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 ] are cited in the Supplementary Materials.…”