Preparation of five- and six- membered cyclic ketones by the palladium-catalyzed cyclization reaction. Application to methyl dihydrojasmonate synthesis
Methyl 3-oxo-8-phenoxy-6-octenoate (1) was cyclized using Pd(OAc)2-PPh3 as a catalyst to give 2-carbomethoxy-3-vinylcyclopentanone (2) and 2-carbomethoxy-4-cycloheptenone (3). The former was the main product in acetonitrile. 2-Alkylated 3-oxo-8-phenoxy-6-octenoates were converted mainly to the five-membered ketones. Based on this cyclization method, methyl dihydrojasmonate (8) was prepared from methyl
Formation of seven- and eight-membered rings by Mn(III)-based oxidative free-radical cyclization.
作者:Barry B. Snider、John E. Merritt
DOI:10.1016/s0040-4020(01)96189-7
日期:1991.10
Oxidative free-radical cyclizations of acetoacetates 1, 8, 17, and 20 with Mn(OAc)3·2H2 and Cu(OAc)2·H2O in acetic acid provide cycloheptenes and cyclooctenes in moderate to good yield. Tandem cyclizations of 28, 35 and 51 provide bicyclo[4.2.1]nonanes, bicyclo[5.2.1]decanes, bicyclo[5.3.0]decanes and bicyclo[6.3.0]undecanes.