A green way to γ-lactams through a copper catalyzed ARGET-ATRC in ethanol and in the presence of ascorbic acid

TY - JOUR

T1 - A green way to γ-lactams through a copper catalyzed ARGET-ATRC in ethanol and in the presence of ascorbic acid

AU - Casolari, Roberto

AU - Felluga, Fulvia

AU - Frenna, Vincenzo

AU - Ghelfi, Franco

AU - Pagnoni, Ugo M.

AU - Parsons, Andrew F.

AU - Spinelli, Domenico

PY - 2011/1/14

Y1 - 2011/1/14

N2 - A 'green' ARGET-ATRC, for the CuCl[PMDETA] catalysed cyclo-isomerization of N-allyl-alpha-polychloroamides to gamma-lactams is described. The process works efficiently (yields 78-96%), uses a bio-solvent, as ethanol, and exploits the reducing feature of ascorbic acid to limit, at a low level (2-4%), the amount of catalyst. To preserve the efficacy of the catalytic cycle, addition of Na2CO3 is essential, which quenches the HCl released during the CuCl[PMDETA] regeneration step. Profitable features of the process are: mild reaction temperatures (25-37 degrees C), relatively short reaction times (usually 5 h) and low solvent volumes (2 mmol of substrate/mL of ethanol). The method, upon stoichiometric adjustment, was also used for the synthesis of alpha,beta-unsaturated-gamma-lactams from N-(2-chloroallyl)-alpha-polychloroamides, via a tandem process involving an ATRC and a reductive [1,2]-elimination. (C) 2010 Elsevier Ltd. All rights reserved.

AB - A 'green' ARGET-ATRC, for the CuCl[PMDETA] catalysed cyclo-isomerization of N-allyl-alpha-polychloroamides to gamma-lactams is described. The process works efficiently (yields 78-96%), uses a bio-solvent, as ethanol, and exploits the reducing feature of ascorbic acid to limit, at a low level (2-4%), the amount of catalyst. To preserve the efficacy of the catalytic cycle, addition of Na2CO3 is essential, which quenches the HCl released during the CuCl[PMDETA] regeneration step. Profitable features of the process are: mild reaction temperatures (25-37 degrees C), relatively short reaction times (usually 5 h) and low solvent volumes (2 mmol of substrate/mL of ethanol). The method, upon stoichiometric adjustment, was also used for the synthesis of alpha,beta-unsaturated-gamma-lactams from N-(2-chloroallyl)-alpha-polychloroamides, via a tandem process involving an ATRC and a reductive [1,2]-elimination. (C) 2010 Elsevier Ltd. All rights reserved.

KW - Halocompounds

KW - ATRC

KW - gamma-Lactams

KW - CuCl

KW - Ascorbic acid

KW - TRANSFER RADICAL POLYMERIZATION

KW - ADDITION ATRA

KW - FUNCTIONAL REARRANGEMENT

KW - ORGANIC-SYNTHESIS

KW - ELECTRON-TRANSFER

KW - REDUCING AGENTS

KW - CYCLIZATION REACTIONS

KW - METHYL-METHACRYLATE

KW - STEREOSELECTIVE-SYNTHESIS

KW - DIRUTHENIUM AMIDINATE

UR - http://www.scopus.com/inward/record.url?scp=78650171575&partnerID=8YFLogxK

U2 - 10.1016/j.tet.2010.11.025

DO - 10.1016/j.tet.2010.11.025

M3 - Article

SN - 0040-4020

VL - 67

SP - 408

EP - 416

JO - Tetrahedron

JF - Tetrahedron

IS - 2

ER -