110790-48-2Relevant academic research and scientific papers
Stepwise Transition Metal Promoted Ring Expansion Reactions of Vinylcyclopropenes to Give Cyclopentadienes and Cyclohexa-2,4-dienones. The First Example of a 1-Metallacyclohexa-2,4-diene Complex,
Grabowski, Norman A.,Hughes, Russell P.,Jaynes, B. Scott,Rheingold, Arnold L.
, p. 1694 - 1695 (1986)
1,2,3-Triphenyl-3-vinylcycloprop-1-ene (1) reacts with 2-C2H4)(PPh3)2> to give the first example of a 1-platinacyclohexa-2,4-diene complex (2) (the crystal structure of which has been determined), with 5-C9H7)(η-C2H4)2> to
Stereoselective ring expansion of 3-vinyl-1-cyclopropenes to give (η5-cyclopentadienyl)ruthenium and (η4-cyclohexadienone)iron complexes. Exclusion of planar metallacyclohexadiene intermediates and relevance to the Do?tz reaction
Hughes, Russell P.,Trujillo, Hernando A.,Gauri, André J.
, p. 4319 - 4324 (2008/10/09)
trans-3-(β-Deuteriovinyl)-1,2,3-triphenyl-1-cyclopropene, 15, reacts with Fe2(CO)9 to give the 2,4-cyclohexadieneone complex 16, as a single isotopomer. The location of deuterium in the endo-position was confirmed by comparison of 1H NMR spectra of 16 with its isotopomer 10 and by conversion of both isotopomers to their bis(trimethylphosphine) derivatives 17a,b. NOE experiments on 17a show a positive interaction between the endo-H and PMe3; this resonance is missing in 17b. Similarly, 15 reacts with [Ru(C5Me5)Cl]4 or [Ru(C5Me5)(MeCN)3]+BF 4- to give only a single isotopomeric ruthenocene 9b, containing no deuterium. Formation of single isotopomers in each reaction excludes any access to a planar metallacyclohexadiene, or any species with a symmetry plane bisecting the CHD group, as an intermediate or transition state along the reaction pathway. Internally consistent mechanisms for formation of the six- and five-membered rings are proposed to account for the stereochemical features of these and related reactions. Analogies are drawn between these reactions and those pathways proposed for the synthetically useful Do?tz reaction for the synthesis of five- and six-membered organic rings.
