R. Rossi*, F. Bellina, L. Mannina
Jan 20, 1997
Citations
0
Influential Citations
18
Citations
Journal
Tetrahedron
Abstract
Abstract (E)- and (Z)-2,3-dibromopropenoates were found to be able to react with Bu3SnXR1 (X = O,S; R1 = alkyl, aryl) in NMP solution at 20 °C in the presence of Pd(PPh3)4 to give the corresponding 3-alkoxy, 3-arylthio and 3-alkylthio substituted products. Under similar conditions methyl (E)- and (Z)-3-bromopropenoate, methyl (Z)-3-iodo-2-octenoate, 3-alkoxycarbonyl substituted (cyclo)alkenyl triflates as well as methyl 3-bromopropiolate, were converted into the corresponding 3-methylthio or 3-phenylthio substituted products when compounds Bu3SnSR1 (R1 Me, Ph) were used as nucleophiles. On the contrary, 2-bromo substituted α,β-unsaturated esters or lactones as well as a 2-substituted alkyl 3-bromopropenoate did not under Pd-mediated substitution reactions by treatment with Bu3SnOR1 and 3-substituted (E)-2,3-dibromopropenoates, and 3-substituted (Z)-3-iodopropenoates afforded the corresponding α,β-acetylenic esters, when reacted with Bu3SnOR1 in the presence of Pd(PPh3)4. A selective monosubstitution reaction also occurred when 1,2-dibromobenzene, was reacted with PhSSnBu3 in toluene in the presence of Pd(PPh3)4. Finally, compounds (E)- and (Z)-22a, which were prepared by Pd-mediated CS bond forming reactions, were used as direct precursors to some natural carboxyamides.