936-52-7Relevant articles and documents
Altering the allowed/forbidden gap in cyclobutene electrocyclic reactions: Experimental and theoretical evaluations of the effect of planarity constraints
Lee, Patrick S.,Sakai, Shogo,Hoerstermann, Peter,Roth, Wolfgang R.,Kallel, E. Adam,Houk
, p. 5839 - 5848 (2003)
The allowed conrotatory cyclobutene ring-opening has a distinctly nonplanar carbon skeleton. Classic experiments by Brauman and Archie, and by Freedman et al., placed the allowed/forbidden gap at greater than 15 kcal/mol. Wolfgang Roth proposed that a system forced to planarity might have a smaller preference for the conrotatory mode than unconstrained systems. Such systems have now been studied theoretically and experimentally, and results that confirm Roth's postulate are presented here. The experiments were performed in Bochum, and the calculations were carried out in Osaka and Los Angeles. As the cyclobutene ring-opening transition structure approaches planarity, the energy gap between allowed conrotatory and the forbidden disrotatory pathways decreases. For the ring-opening of a cyclobutene fused to norbornene, the energy gap between the forbidden and the allowed transition state is only 4.1 kcal/mol by CASSCF and 8.0 kcal/mol by CAS-MP2 as compared to 13.4 and 19.2 kcal/mol, respectively, for the parent cyclobutene. Experimental studies of 3,4-dimethylcyclobutenes fused to various ring systems are reported, and a trend is found toward a reduced allowed/forbidden gap as the planarity of the cyclobutene is enforced.
Decomposition of an oxodiazirine: Free versus incarcerated within the cavities of two α-cyclodextrins
Mieusset, Jean-Luc,Thiel, Bernhard,Abraham, Michael,Pa?ar, Mirjana,Brinker, Udo H.
, p. 681 - 683 (2013)
The chemistry of oxodiazirine 1 was investigated by photolyzing its α-cyclodextrin (6-Cy) complex, for which a Job plot indicated a 1:2 guest-to-host stoichiometry. Solid-phase photolysis of 16-Cy)2 produced tricyclo[3.3.0.02,8]octan-3-one (3) and bicyclo[3.3.0]oct-5- en-3-one (4) in a 93:7 ratio. In contrast, gas-phase thermolysis of free 1 resulted in a 47:53 ratio of products 3 and 4. Thus, incarceration of a guest compound within a fitting microenvironment of two host molecules leads to a strongly enhanced chemoselectivity, even when highly reactive species, such as carbenes, are involved.
Method for preparing alkane carboxylic acid by increasing alkane carbon chains
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Paragraph 0031; 0050-0052, (2021/06/09)
The invention discloses a method for preparing alkane carboxylic acid by increasing alkane carbon chains. The method comprises the following steps: (1) carrying out Stork enamine alkylation on cyclopentanone or cyclohexanone and a secondary amine compound to generate a corresponding 1-position secondary amine substituted cyclopentene or cyclohexene crude product, namely Stork enamine; (2) carrying out electrophilic reagent reaction on the Stork enamine and acyl halide to form a 2-acyl cyclic ketone compound; and (3) carrying out ring opening on the 2-acyl cyclic ketone compound under the action of alkali to generate a carbonyl carboxylic acid compound, and carrying out a Wolff-Huang Minglong reduction reaction on the carbonyl carboxylic acid compound to obtain the corresponding alkane carboxylic acid. According to the method disclosed by the invention, cyclopentanone or cyclohexanone can be flexibly selected to meet the requirement of increasing different carbon numbers according to the required carbon number and different sources of target carburant alkane carboxylic acid or corresponding acyl halide. The method has the advantages of simple reaction process and no complex operation difficulty, and is suitable for industrial mass production.
One-Pot Synthesis of 3-Oxocycloalka[c]pyridines
Geronikaki, A.,Hakobyan, E. K.,Hovakimyan, A. A.,Kartsev, V. G.,Sirakanyan, S. N.
, p. 1748 - 1752 (2021/12/13)
Abstract: A new efficient one-pot procedure has been developed for the synthesis of 1-substituted partially hydrogenated 3-oxocycloalka[c]pyridine-4-carbonitriles by reaction of cyclopentanone or cyclohexanone with morpholine, acyl chloride, and cyanoacetamide. The proposed procedure is advantageous due to shorter reaction time and smaller amounts of the solvents and reactants.
