Synthesis of alkyl 2,5-dihydro-5-oxofuran-2-carboxylates via palladium-catalyzed carbonylative cyclization of β-bromovinyl aldehydes in alcohols

Ligand‐free CuI‐catalyzed coupling and cyclization of β‐bromo‐α,β‐unsaturated amides with formamide leading to pyrimidinones

“…Transition metal‐catalyzed coupling followed by cyclization has been widely explored and used as a promising synthetic tool for the construction of the structural core of many pharmacologically and biologically active heterocyclic compounds . As part of our continuing studies directed towards transition metal‐catalyzed cyclization reactions, we recently disclosed new synthetic methods for the formation of several carbo‐ and heterocyclic compounds using β‐bromo‐α,β‐unsaturated aldehydes and their derivatives via such an intrinsic coupling and cyclization . The β‐bromo‐α,β‐unsaturated aldehydes and their derivatives can be readily prepared from the corresponding α‐methylene‐containing ketones by the bromination conditions of the Vilsmeier–Haak reaction and subsequent transformation and used as a building block for the synthesis of versatile cyclic compounds .…”

Microwave‐assisted copper powder‐catalyzed coupling and cyclization of β‐bromo‐α,β‐unsaturated amides with amidine hydrochlorides leading to pyrimidinones

“…Thus, such scaffold‐containing compounds have been synthesized and tested for biological activity. During the course of our continuing studies directed towards transition metal‐catalyzed cyclization reactions of β‐bromo‐α,β‐unsaturated aldehydes and their derivatives, we have identified several new methods for the synthesis of carbocyclic and heterocyclic compounds . β‐Bromo‐α,β‐unsaturated aldehydes and their derivatives are readily prepared from α‐methylene group‐containing ketones by bromination under Vilsmeier–Haack conditions and subsequent transformation, and the products can serve as valuable building blocks for the construction of various cyclic compounds .…”

Palladium‐catalyzed carbonylative cyclization of 3‐bromoallyl alcohols leading to furan‐2(5H)‐ones

“…During the course of our ongoing studies on palladium‐catalyzed cyclization reactions using β‐bromo‐α, β‐unsaturated aldehydes and their derivatives, which are readily prepared from the corresponding ketones by Vilsmeier–Haack reaction and subsequent transformation and used as a building block for the construction of versatile cyclic compounds, we recently reported on the synthesis of several heterocycles via such a carbonylative cyclization. For example, β‐bromovinyl aldehydes were found to be cyclized under carbon monoxide pressure in MeCN and alcohols in the presence of a palladium catalyst to give furan‐2(5 H )‐ones . Such a similar palladium‐catalyzed carbonylative cyclization was also exemplified by the reaction of β‐bromo‐α, β‐unsaturated ketones under carbon monoxide pressure to give ( Z )‐alkylidenefuranones .…”