22589-13-5Relevant 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.
, p. 2342 - 2345 (2011)
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.
Synthesis of Multifunctional Spirocyclic Azetidines and Their Application in Drug Discovery
Kirichok, Alexander A.,Shton, Irina O.,Pishel, Irina M.,Zozulya, Sergey A.,Borysko, Petro O.,Kubyshkin, Vladimir,Zaporozhets, Olha A.,Tolmachev, Andrei A.,Mykhailiuk, Pavel K.
supporting information, p. 5444 - 5449 (2018/04/23)
The synthesis of multifunctional spirocycles was achieved from common cyclic carboxylic acids (cyclobutane carboxylate, cyclopentane carboxylate, l-proline, etc.). The whole sequence included only two chemical steps—synthesis of azetidinones, and reduction into azetidines. The obtained spirocyclic amino acids were incorporated into a structure of the known anesthetic drug Bupivacaine. The obtained analogues were more active and less toxic than the original drug. We believe that this discovery will lead to a wide use of spirocyclic building blocks in drug discovery in the near future.
Asymmetric pericyclic cascade approach to spirocyclic oxindoles
Richmond, Edward,Duguet, Nicolas,Slawin, Alexandra M. Z.,Lebl, Tomas,Smith, Andrew D.
supporting information; experimental part, p. 2762 - 2765 (2012/07/14)
The reaction of chiral N-arylnitrones with carbocyclic alkylarylketenes generates spirocyclic oxindoles in good yields and with excellent levels of enantioselectivity (90-99% ee) via a pericyclic cascade process.
Kinetics and Mechanism of Hydration of Alkylketenes
Allen, Annette D.,Tidwell, Thomas T.
, p. 2774 - 2780 (2007/10/02)
The hydration reactivities of CH2=C=O (1), t-Bu2C=C=O (5), Et2C=C=O (7), (CH2)4C=C=O (8), (CH2)5C=C=O (9), and t-BuCH=C=O (10) in H2O or H2O/CH3CN mixtures have been examined, including acid and base catalysis and solvent and structural isotope effects.These results provide the first systematic comparison of structural effects on the hydration of aliphatic ketenes, as well as the first measurements of base-induced hydration and pH-rate profiles for this process.The significant steric and electronic effects of the substituents observed lead to the interpretation that the acid-catalyzed reaction involves rate-limiting proton transfer to Cβ perpendicular to the ketene plane, while the H2O- and OH--induced reactions involve nucleophilic attack in the ketene plane.These results resolve the many conflicting previous reports and interpretations regarding ketene hydration.
Generation, Alkylation, and Silylation of Directed Enolates Formed by Reaction of Ketenes and Organolithium Reagents
Baigrie, Lynn M.,Lenoir, Dieter,Seikaly, Hani R.,Tidwell, Thomas T.
, p. 2105 - 2109 (2007/10/02)
Symmetrical ketenes R2C=C=O R2=t-Bu2(1), Et2(2),(CH2)4(3),(CH2)5(4) were reacted with organolithium reagents R'Li to give directed enolates R2C=C(OLi)R' which were alkylated with MeI or silylated with Me3SiCl.The silylation results for 2-4 were compared to those for reaction of ketones R2CHCO-n-Bu (16-18) with Me3SiCl and either i-Pr2NLi, KH, or Et3N.These latter conditions usually favored different regioisomers from the ketene route.Reaction of 1 with t-BuLi gave the previously inaccessible enolate t-Bu2C=C(OLi)-t-Bu (25), which on reaction with MeI gave a mixtureof the O-methylation product 27 along with some C-methylation product and with Me3SiCl gave the silyl enol ether 26.The vinyl ethers 26 and 27 are among the first substituted tri-tert-butylethylenes which have been reported.
Trimethylsilyl Cyanide - A Reagent for Umpolung, VIII. Derivatives of 2-(Trimethylsilyloxy)-2-propenenitrile. Syntheses and General Properties
Hertenstein, Ulrich,Huenig, Siegfried,Reichelt, Helmut,Schaller, Rainer
, p. 261 - 287 (2007/10/02)
Rather different derivatives of the new title compuond 7 were synthesized by routes A - H (Table 2 and 3).The effects of substituents and reaction routes on the E/Z ratios (NMR) is discussed.Replacement of SiMe3 in 7 by RCO- and MeSO2- yields other alkenes with donor (O - X) and acceptor groups (CN) at the same C-atom.Their opposite effects on the β-C-atom is estimated from the corresponding 1H- and 13C-NMR signals.
