34667-97-5Relevant academic research and scientific papers
Formation of 2-[1-(Trimethylsilyl)alkylidene]-4-cyclopentene-1,3-dione from Lewis Acid-Catalyzed Reaction of Cyclobutenedione Monoacetal with Alkynylsilane: Novel Cationic 1,2-Silyl Migrative Ring Opening and Subsequent 5-Exo-Trig Ring Closure
Yamamoto, Yoshihiko,Noda, Masashi,Ohno, Masatomi,Eguchi, Shoji
, p. 1292 - 1298 (1997)
An ethoxycarbenium ion intermediate, which was produced by the catalytic action of a Lewis acid on a cyclobutenedione monoacetal, reacted with phenyl(trimethylsilyl)acetylene to give a normal electrophilic substitution product. In sharp contrast, the same
Four-Electron Electrocyclic Ring-Opening/Intermolecular [4+2] Cycloadditions of α-Hydroxycyclobutenones: Stereoselective Synthesis of Multiple Substituted δ-Lactams
Song, Peidong,Li, Qing,Wang, Congcong,Wu, Wenfa,Mao, Xu,Wang, Jiajia,Hu, Xiangdong
supporting information, p. 1208 - 1212 (2016/04/26)
A four-electron electrocyclic ring-opening/intermolecular [4+2] cycloaddition of α-hydroxycyclobutenones is reported. The reaction represents the first example for the intermolecular cycloaddition of the extensively studied enol-ketene intermediate, and provides a new synthetic route to multiply substituted δ-lactams in high stereoselectivity.
Organoytterbium ate complexes extend the value of cyclobutenediones as isoprene equivalents
Packard, Emma,Pascoe, David D.,Maddaluno, Jacques,Goncalves, Theo P.,Harrowven, David C.
supporting information, p. 13076 - 13079 (2014/01/06)
Changing course: While organolithium and Grignard reagents favor addition to C1 of A (R=Me), the corresponding organoytterbium reagents add to C2 (R=tBu). Computational studies provide insights into the nature of organoytterbium species and their reactivity, and a total synthesis of (-)-mansonone B illustrates the utility of the method in terpenoid synthesis. Tf=trifluoromethanesulfonyl.
Reactive iron carbonyl reagents via reaction of metal alkoxides with Fe(CO)5 or Fe2(CO)9: Synthesis of cyclobutenediones via double carbonylation of alkynes
Beesu, Mallesh,Periasamy, Mariappan
experimental part, p. 543 - 549 (2011/04/16)
Alkoxy bases such as t-BuOK react with Fe(CO)5 to give reactive iron carbonyl intermediates that in turn react with alkynes at 70 °C in THF to give 1,2-cyclobutenediones in 70-93% yields after CuCl2· 2H2O oxidation. A novel 1,2-diacyloxyferrole derivative was isolated in the reaction of diphenylacetylene with Fe(CO)5/t-BuOK in the presence of acetyl chloride in contrast to the formation of a 1,4-diacyloxyferrole complex formed in the reaction using Fe(CO) 5/Me3NO. The Fe2(CO)9/t-BuOK reagent system also converts the alkynes to corresponding cyclobutenediones in 63-90% yields under similar reaction conditions.
A simple and convenient method for the synthesis of cyclobutenediones from alkynes using new Fe(CO)5/NaH/MeI reagent system
Periasamy, Mariappan,Beesu, Mallesh,Shyam Raj
, p. 2843 - 2846 (2008/12/21)
Iron carbonyl complexes prepared in situ using the Fe(CO)5/NaH/MeI reagent combination and alkynes at 25 °C give the corresponding cyclobutenediones in 50-65% yields after CuCl2 · 2H2O oxidation.
Generation of 1,2-bisketenes from cyclobutene-1,2-diones by flash photolysis and ring closure kinetics
Allen, Annette D.,Colomvakos, Jim D.,Diederich, Fran?ois,Egle, Ian,Hao, Xiaokuai,Liu, Ronghua,Lusztyk, Janusz,Ma, Jihai,McAllister, Michael A.,Rubin, Yves,Sung, Kuangsen,Tidwell, Thomas T.,Wagner, Brian D.
, p. 12125 - 12130 (2007/10/03)
The interconversion of cyclobutene-1,2-diones (1) and 1,2-bisketenes (RC-C-O)2 has been surveyed for different combinations of substituents R = H, Me, t-Bu, Ph, Me3Si, CN, Cl, Br, R1O, alkynyl, and PhS. The bisketenes 2 have been generated by flash photolysis, and the kinetics of their conversion to 1 have been studied by time-resolved infrared and ultraviolet spectroscopy. The rate constants of the ring closure of 2 are correlated by the ketene stabilization parameters (SE) and with calculated barriers. The rate constant of ring closure of the di-tert-butyl bisketene 2g to cyclobutenedione 1g is only 40 times smaller than for the dimethyl analogue, showing a rather modest steric barrier. The quinoketene 2s has a fast rate of ring closure, but not as fast as anticipated on the basis of calculated geometric and thermodynamic factors. A lag in the attainment of aromatic stabilization in the transition structure for ring closure is a possible cause of this diminished reactivity.
Facile addition of dichloroketene to acetylenes mediated by zinc and ultrasound
Parker,Rizzo
, p. 2781 - 2789 (2007/10/02)
The addition of dichloroketene, generated from trichloroacetyl chloride, zinc dust and ultrasound, to terminal and internal acetylenes is reported. This procedure is a more convenient alternative to Zn-Cu couple.
SYNTHESIS OF SUBSTITUTED CYCLOBUTENEDIONES BY THE PALLADIUM CATALYZED CROSS-COUPLING OF HALOCYCLOBUTENEDIONES WITH ORGANOSTANNANES
Liebeskind, Lanny S.,Wang, Jianying
, p. 4293 - 4296 (2007/10/02)
Halo-substituted cyclobutenediones undergo palladium catalyzed cross-coupling with organostannanes providing a mild method for the synthesis of substituted cyclobutenediones.
3-Stannylcyclobutenediones as Nucleophilic Cyclobutenedione Equivalents. Synthesis of Substituted Cyclobutenediones and Cyclobutenedione Monoacetals and the Beneficial Effect of Catalytic Copper Iodide on the Stille Reaction
Liebeskind, Lanny S.,Fengl, Richard W.
, p. 5359 - 5364 (2007/10/02)
Treatment of 3,4-diisopropoxycyclobutenedione with n-Bu3SnSiMe3/catalytic CN- furnished 3-isopropoxy-4-(tri-n-butylstannyl)cyclobutenedione in 65 percent yield.This compound cross-coupled with organic iodides attached to sp2- and sp-
Reactions with Cyclobutenediones, LIX. - New Syntheses of 3-Alkyl-4-phenylcyclobutene-1,2-diones
Ried, Walter,Vogl, Manfred
, p. 355 - 359 (2007/10/02)
The 3-alkyl-4-phenylcyclobutene-1,2-diones 4a-e have been prepared by degradation of the cyclobutene-1,2-diones 3a-e.The compounds 4a and 4b can also be obtained by hydrolysis of the cycloaddition products 5a and 5b.
