4233-18-5Relevant academic research and scientific papers
Oxyallyl Exposed: An Open-Shell Singlet with Picosecond Lifetimes in Solution but Persistent in Crystals of a Cyclobutanedione Precursor
Kuzmanich, Gregory,Spaenig, Fabian,Tsai, Chao-Kuan,Um, Joann M.,Hoekstra, Ryan M.,Houk,Guldi, Dirk M.,Garcia-Garibay, Miguel A.
supporting information; scheme or table, p. 2342 - 2345 (2011/05/04)
Photoinduced decarbonylation of 2,4-bis(spirocyclohexyl)-1,3- cyclobutanedione 1 in the crystalline solid state resulted in formation of a deep blue transient with λmax = 550 nm and a half-life of 42 min at 298 K, identified as kinetically stabilized oxyallyl. Support for an open-shell singlet species was obtained by spectroscopic analysis and (4/4) CASSCF calculations with the 6-31+G(d) basis set and multireference MP2 corrections. The electronic spectrum of the singlet biradical, confirmed by femtosecond pump-probe studies in solution, was matched by coupled cluster calculations with single and double corrections.
Nitrosonium salts, NO+X- (X = B(3,5-diCF 3Ph)4- or PW12O40 3-), as electrophilic catalysts for alkene activation in arene alkylation and dimerization reactions
Khenkin, Alexander M.,Neumann, Ronny
supporting information; body text, p. 11876 - 11877 (2009/02/05)
It has been found that in apolar reaction media the nitrosonium cation (NO+) activated alkenes under mild conditions toward electrophilic substitution of arene substrates to yield the alkylated arene with Markovnikov orientation. In the absence of arenes the alkenes react with themselves to yield a mixture of dimeric alkenes. The nitrosonium cation can be dissolved in the reaction medium by using the tetrakis-(bis-(3,5-trifluromethyl)phenyl) borate anion, where upon the reactions occur effectively at 30 °C. Alternatively an insoluble, heterogeneous catalyst was prepared so as to yield a NO+ cation with a polyoxometalate (PW12O403-) anion. This catalyst was generally more effective and selective toward a broader range of substrates at 70 °C. Copyright
Insights into the general and efficient cross McMurry reactions between ketones
Duan, Xin-Fang,Zeng, Jing,Lue, Jia-Wei,Zhang, Zhan-Bin
, p. 9873 - 9876 (2007/10/03)
The selective cross McMurry couplings of diaryl or aryl ketones with various substituted ketones were achieved in 53-94% isolated yields. It is believed that the strong affinity of the substituents to the low-valent titanium surface plays an important role in regards to moderating selectivity. Through the introduction of such substituents followed by their removal post McMurry coupling, structurally similar ketones can be effectively cross-coupled.
HYDROGENATION AND OTHER SIDE-REACTIONS DURING THE REDUCTIVE COUPLING OF KETONES WITH LOW-VALENT TITANIUM (McMurry Synthesis).
Dams, R.,Malinowski, M.,Geise, H. J.
, p. 311 - 320 (2007/10/02)
Active titanium slurries, effective in the McMurry coupling reaction of ketones to olefins, are also hydrogenation agents.Sometimes they also promote isomerisation of the originally formed olefin as well as aldol type and pinacol type condensations under special reaction conditions. The most prominent factors promoting hydrogenation are the use of high ratios LiAlH4 : TiCl3 and low temperatures in the formation of the low-valent titanium species.
Studies on the Pinacol Coupling Reaction
Mundy, Bradford P.,Srinivasa, Ramanujan,Kim, Youseung,Dolph, Thomas,Warnet, Ronald J.
, p. 1657 - 1661 (2007/10/02)
The mixed pinacol coupling reaction has been carefully analyzed.Although a trend toward statistical distribution of products can be found, it is observed that true statistical distributions are rarely observed.Ring-size and alkyl substituent effects are examined.A through-space heteroatom influence on coupling is noted.By use of (R)-(+)-3-methylcyclohexanone, a very specific effect of coupling conditions on product stereochemistry is observed.
Reactions of Cyclohexanone with Metal Vapors
Miller, Jeffrey T.,DeKock, Carroll W.
, p. 516 - 520 (2007/10/02)
Metal atom vapors of several d and f transition elements were cocondensed with cyclohexanone at -196 deg C.Radical reduction of cyclohexanone to -1,1'-diol, a pinacol, was observed for elements which are both highly electropositive and form strong metal-oxygen bonds, for example, the early transition, lanthanide, and actinide elements.High yields of aldol condensation products were produced along with a small amount of bicyclohexylidene.Metal atoms of the latter transition elements were much less reactive with cyclohexanone and did not yield a pinacol product.Titanium clusters were prepared by codepositing titanium atoms with a large excess of solvent.Titanium clusters were less reactive than titanium atoms toward cyclohexanone radical reduction reactions.High surface area titanium powders produced by solution techniques yield pinacols when cyclohexanone reacts in excess and further deoxygenate pinacolic dianions to olefins under conditions of limited stoichiometry.
UNUSUAL REDUCTIVE CONDENSATIONS IN THE REACTION OF DIIODODIMETHYLSILANE WITH KETONES
Ando, Wataru,Ikeno, Masayuki
, p. 1255 - 1256 (2007/10/02)
Diiododimethylsilane reacts with various ketones in the presence of zinc to give the corresponding reductive condensation products in good yields.
