113541-29-0Relevant academic research and scientific papers
Intramolecular Cyclopropanation Reaction of Furanyl Diazo Ketones
Padwa, Albert,Wisnieff, Thomas J.,Walsh, Edward J.
, p. 299 - 308 (2007/10/02)
α-Diazo ketones derived from furanyl- and benzofuranylpropionic acids were prepared, and their rhodium(II) acetate catalyzed behavior was studied.The results are consistent with a mechanism in which the key step involves addition of a keto carbenoid intermediate on to the furanyl ?-bond followed by an electrocyclic ring-opening reaction.In the case of the benzo-substituted furanyl system, the suspected bicyclic intermediate was isolated in high yield and its chemistry was subsequently investigated.The bicyclic ketone derived from 1-diazo-4-(2-benzofuryl)-2-butanone undergoes a novel thermal rearrangement to a benzopyranone derivative.This unexpected transformation can be rationalized in terms of a -cycloreversion reaction to give an ortho-quinoidal intermediate, which undergoes a subsequent electrocyclic ring closure followed by a 1,3-hydrogen shift.Furans with side chains of various lengths containing a diazomethyl keto group were also studied.The cyclization chemistry of the closely related diazothienylalkanone system was investigated and found to give products derived from an analogous intramolecular cyclopropanation reaction.
131. Synthesis of 2-Cycloalkenones (Parts of 1,4-Diacyl-1,3-butadiene Systems) and of a Heterocyclic Analogue by Metal-Catalyzed Decomposition of 2-Diazoacylfurans
Wenkert, Ernest,Guo, Ming,Pizzo, Ferdinando,Ramachandran, Kishore
, p. 1429 - 1438 (2007/10/02)
Furans with side-chains at C(2) of various lengths terminating in diazomethyl keto groups are shown to undergo Rh2(OAc)4-catalyzed furan unravelling with the production of 2-cyclopentenone, 2-cyclohexenone, and 2-cycloheptenone to each of whose olefinic C(β) is attached an acrylaldehyde unit.Interposition of a cyclohexane or a methylaminomethylene moiety between the furan and diazoketo functions leads to the formation of a hydroindenone and pyrrolone, respectively.Replacement of the diazomethylketo terminus by an α-diazoethylketo system or a α-diazo-β-keto-ester function produces 2-substituted 2-cycloalkenones.A furan with a C4, diazomethylketo-terminating side-chain at C(3) is described to be transformed into a 4-formylmethylidene-2-cyclohexenone.
