Mechanismus der Cyclotrimerisierung von Phenylvinylketonen und die Kristallstrukturen von 1-((1R*,2S*,3R*,5S*)-und 1-((1R*,2S*,3R*,5R*)- 3.5-Dibenzoyl-2-hydroxy-2-phenylcyclohexylmethyl)-pyrrolidin-2-on/The Mechanism of Cyclotrimerisation of Phenylvinylketones and theCrystal Structures of 1-((1R*,2S*,3R*,5S*)-and1-((1R*,2S*,3R*,5R*)-3.5-Dibenzoyl-2-hydroxy-2-phenylcyclohexylmethyl)-pyrrolidin-2-on
AbstractThe cyclotrimerisation of 1-phenyl-2-propyn-1-ol (1) with pyrrolidin-2-one (2) to the tribenzoylcyclohexanes 4 and 5 produced -with modifications of the reaction conditions -the phenylvinylketone adducts 17 and 18 as intermediates and additionally the cyclohexylmethyl-pyrrolidin-2-ones 8 and 9. Obviously the mechanism consists of a primary attack of pyrrolidin-2-onat (2a) to a phenylketone (7) followed by a series of consecutive Michael reactions, which give rise to 4 and 5 as well as to 8 and 9. The latter two have been identified by X-ray crystal structure analyses. They crystallize in the monoclinic space group P21/c, Z=4, with 8: a = 1786,8(6), b = 636.7(2), c = 2280.9(8) pm, β = 102.33(3)°; 9: a = 1119.9(7), b = 1165.1(3), c = 2198.6(5) pm, β = 118.24(4)°.