134225-41-5Relevant academic research and scientific papers
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.
