Sc(OTf)3 is an effective catalyst for bis-carbomethoxylation of aliphatic diamines with dimethyl carbonate (DMC) under very mild conditions. At ambient temperature (293 K), in the presence of Sc(OTf)3, aliphatic diamines, such as 1,6-diaminohexane (1), 1,4-diaminobutane (2), 1,3-diaminopropane (3), meta-xylylenediamine (4) and para-xylylenediamine (5), react with DMC to afford the corresponding dicarbamates in high yields. The carbomethoxylation reaction is highly selective (100%). Under the used working conditions, side-reactions, such as formation of ureas and/or N-methyl derivatives, are repressed. The starting catalyst, Sc(OTf)3, modifies during the catalytic process and converts into Sc-methoxo species by losing OTf groups, as the isolation of unprecedented mono-urethane triflic salts, (MeO(O)CNH–R– NH3)O3SCF3 (R = –(CH2)6–, meta-C6H4(CH2)2–), also indicates. The modified catalyst can be recovered at the end of the reaction and recycled.
“Highly selective carbamation of aliphatic diamines under mild conditions using Sc(OTf)3 as catalyst and dimethyl carbonate as a phosgene substitute” , 2006, 66(1-2), 72-80
QUARANTA, Eugenio
2006-01-01
Abstract
Sc(OTf)3 is an effective catalyst for bis-carbomethoxylation of aliphatic diamines with dimethyl carbonate (DMC) under very mild conditions. At ambient temperature (293 K), in the presence of Sc(OTf)3, aliphatic diamines, such as 1,6-diaminohexane (1), 1,4-diaminobutane (2), 1,3-diaminopropane (3), meta-xylylenediamine (4) and para-xylylenediamine (5), react with DMC to afford the corresponding dicarbamates in high yields. The carbomethoxylation reaction is highly selective (100%). Under the used working conditions, side-reactions, such as formation of ureas and/or N-methyl derivatives, are repressed. The starting catalyst, Sc(OTf)3, modifies during the catalytic process and converts into Sc-methoxo species by losing OTf groups, as the isolation of unprecedented mono-urethane triflic salts, (MeO(O)CNH–R– NH3)O3SCF3 (R = –(CH2)6–, meta-C6H4(CH2)2–), also indicates. The modified catalyst can be recovered at the end of the reaction and recycled.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.