147298-33-7Relevant academic research and scientific papers
A comparative Study of the Decomposition of o-Alkynyl-Substituted Aryl Diazo Ketones. Synthesis of Polysubstituted β-Naphthols via Arylketene Intermediates
Padwa, Albert,Chiacchio, Ugo,Fairfax, David J.,Kassir, Jamal J.,Litrico, Angelo,at al.
, p. 6429 - 6437 (2007/10/02)
The photochemical, thermal, and rhodium-catalyzed decomposition reactions of several closely related o-alkynyl or o-alkenyl α-diazoaceto- and propiophenone derivatives have been studied.The reaction outcome is markedly dependent upon the reaction conditions employed for nitrogen extrusion.Thermolysis or photolysis of o-alkynyl α-diazopropiophenone derivatives yields polysubstituted β-naphthols.These products are derived from Wolff rearrangement of the initially formed carbene to give an aryl ketene which undergoes intramolecular cyclization onto the o-alkynylsubstituent.In direct contrast to the thermal and photochemical results, Rh(II)-catalyzed decomposition yields products derived from direct attack of a rhodium carbenoid onto the tethered ?-system producing a vinyl carbenoid intermediate.Further reaction of the cyclized carbenoid with the starting diazo compound furnished a vinyl indenone which undergoes a rapid intramolecular Diels-Alder reaction to produce a novel dimer whose structure was elucidated by an X-ray crystal analysis.Replacement of the methyl group on the diazo center with a sterically less demanding hydrogen atom was also found to play an important role in controlling the outcome of the Rh(II)-catalyzed reaction.
Rearrangement of alkynyl and vinyl carbenoids via the rhodium(II)-catalyzed cyclization reaction of α-diazo ketones
Padwa, Albert,Austin, David J.,Gareau, Yves,Kassir, Jamal M.,Xu, Simon L.
, p. 2637 - 2647 (2007/10/02)
o-Alkynyl-substituted α-diazoacetophenones undergo facile cyclization to indenone derivatives upon treatment with catalytic quantities of Rh(II) carboxylates. The cyclization reaction involves addition of a rhodium stabilized α-keto carbenoid onto the neighboring acetylenic π-bond to give a cyclized vinyl carbenoid. When an alkene is tethered to the alkynyl group, the vinyl carbenoid complex undergoes further cyclization to produce a cyclopropenyl-substituted indenone. Different enyl substituents resulted in a significant variation in the behavioral pattern of the reactive cyclopropene ring. The strained cyclopropene ring was intercepted with diphenylisobenzofuran to give Diels-Alder cycloadducts. For alkynyl substituted π-diazo ketones, the resulting vinyl alkynyl carbenoids were found to give products derived from an unusual alkynyl carbenoid rearrangement. The Rh(II)-catalyzed reaction of several o-dialkynyl-substituted α-diazoacetophenones which contain a group capable of undergoing reaction with the carbenoid at the terminal position was examined. Products derived from a 1,2-hydrogen shift as well as cyclopropanation of a tethered alkene was obtained in high yield. In addition, the thermal decomposition of a series of aziridinylimines derived from alkynyl-substituted aldehydes led to products derived from a rearranged alkynyl carbene. The initially formed alkynyl carbene at C1 could be induced to undergo exclusive reaction at the C3 terminal position.
