114646-77-4Relevant academic research and scientific papers
Ene di- and trimerization of 1-methyl-2-phenylcyclopropene
Lin, Hung-Chun,Tsai, Ru-Ting,Wu, Hsiao-Pin,Lee, Hsin-Yi,Lee, Gon-Ann
, p. 184 - 191 (2015/12/23)
1,2-Disubstituted cyclopropene, 1-methyl-2-phenylcyclopropene (18), was generated by bromo-lithium exchange of 1-bromo-2-phenylcyclopropene followed by treatment with methyl iodide. Compound 18 was oxidized by oxygen to give the α,β-unsaturated carbonyl product 25 and diketone 27 and the tautomeric, β-hydroxyl-α,β-unsaturated ketone 28. However, compound 28 reacted further with the cyclopropene 18 in a retro-Claisen-like reaction to generate adduct 26. Furthermore, compound 18 underwent ene dimerization in neat condition to form the endo-dimer 40 and exo-dimer 41 followed by oxidization with oxygen to give aldehyde 39. It is noteworthy that the endo-dimer 40 and exo-dimer 41 could be trapped with thiophenol to give adduct 42 and 43. In addition, the ene reaction of exo-dimer 41 with monomer 18 gave an exo-exo ene trimer 46 through an exo-transition state which was also trapped by thiophenol to give adducts 44 and 45.
Asymmetric synthesis of 4,4-disubstituted-2-cyclohexen-1-ones from a chiral 2-(trimethylsilyl)benzamide
Schultz, Arthur G.,Pettus, Liping
, p. 5433 - 5436 (2007/10/03)
Birch reduction-alkylation of the chiral 2-(trimethylsilyl)benzamide 4 provides 1,4-cyclohexadienes 5b-5e with diastereomer ratios of >100:1. The conversions of 5b-5e to the 4,4-disubstituted-2-cyclohexen-1-ones 8b-8e are described.
Novel chemoselective and diastereoselective iron(III)-catalysed Michael reactions of 1,3-dicarbonyl compounds and enones
Christoffers, Jens
, p. 3141 - 3149 (2007/10/03)
Iron(III) chloride hexahydrate catalyses the Michael reaction of 1,3-dicarbonyl compounds with α,β-unsaturated ketones under mild and neutral conditions with extraordinary efficiency. The chemoselectivity of this FeIII-catalysed process is superior to that of the classic base-catalysed Michael reaction, since the latter suffers from various side reactions, namely drawbacks such as aldol cyclisations and ester solvolysis. Excellent yields and chemoselectivities together with the environmentally friendly nature of FeIII catalysis makes this an important alternative to classic base catalysis. Moreover, the reaction procedure is reasonably easy: FeIII catalysis does not require inert or anhydrous conditions, and in most cases no solvent is needed. In terms of diastereoselectivity, the FeIII-mediated reaction may also prove superior to a base-catalysed one. In at least one example, FeIII catalysis forms a diastereoisomer as the major kinetic product, which is disfavoured in the base-mediated Michael reaction, where a thermodynamic mixture is obtained. The relative configuration of the diastereoisomeric Michael products has been determined for two examples by synthesis and structure elucidation of the cyclic aldol derivatives.
PREPARATION OF ACYCLIC α-METHYLENE KETONES: PALLADIUM-CATALYZED COUPLING OF ACID CHLORIDES WITH ORGANOTIN REAGENTS
Renaldo, A. F.,Ito, Hiroshi
, p. 1823 - 1830 (2007/10/02)
The reaction of organotin reagents with acid chlorides, catalyzed by palladium (0), provides a general entry to α-substituted unsaturated ketones.
