Use of Polymer-Supported 4-(N,N-Dimethylamino)pyridine in a Formal Conjugate Addition/Elimination Mediated by an N-Ylide Generated In Situ for the Construction of Highly Functionalized Itaconimides/Alkenes

Abstract

A simple and mild metal free cascade reaction has been developed for the construction of highly functionalized olefines. The approach relies on the initial formation of [3+2] cycloadducts from in-situ generated pyridinium ylide (from polymer bounded DMAP) with N-substituted maleimides/α,β-unsaturated β-keto esters. The cycloadducts decompose to regenerate supported DMAP and yield functionalized itaconimides/olefines. The methodology has broad substrates scope. The alkene has been further transformed to trisubstituted furan. PS-DMAP is reused for five cycles.

Pyridinium Ylide-Mediated Diastereoselective Synthesis of Spirocyclopropanyl-pyrazolones via Cascade Michael/Substitution Reaction

“…32−35 There are several reports on polymer-supported pyridine and its derivatives which are utilized in organic transformations. 36,37 Most of the supported pyridines are used as ligands for catalytic reactions such as pybox to construct metal complexes for innumerable catalytic processes. 38−43 Recently, our group developed novel polystyrene-supported pyridines that mediated the diastereoselective synthesis of trans-dihydroidoles 44 and 2,3-dihydrobenzofurans 45 via in situ ylide formation.…”

“…To date, organic chemists have been highly devoted to develop new sustainable methodologies for eco-friendly and green chemistry as well as less time-consuming workup or purification processes. , However, several promising techniques have been developed including the use of solid-supported reagents or catalysts to enable recovery and recycling. Supported analogs have various advantages such as reusability, less waste generation, simplified product purification, sustainability, economics, etc. − There are several reports on polymer-supported pyridine and its derivatives which are utilized in organic transformations. , Most of the supported pyridines are used as ligands for catalytic reactions such as pybox to construct metal complexes for innumerable catalytic processes. − Recently, our group developed novel polystyrene-supported pyridines that mediated the diastereoselective synthesis of trans -dihydroidoles and 2,3-dihydrobenzofurans via in situ ylide formation.…”

Reusable Supported Pyridine-Mediated Cascade Synthesis of trans-2,3-Dihydroindoles via In Situ-Generated N-Ylide

“…However, the potential of N -ylide chemistry has not yet been explored for the construction of indoline derivatives. Nevertheless, considerable attention has been paid to N -ylide-mediated C–C and C–X bond formation in the past few decades . Despite N -ylide stability and selectivity challenges, several efficient routes for construction of heterocycles have been established using cycloaddition and n +1 cyclization processes .…”

A reusable polymer anchored pyridine mediated formal [4 + 1] annulation reaction for the diastereoselective synthesis of 2,3-dihydrobenzofurans

“…8 Besides, in situ generated ammonium ylides have emerged as powerful synthons for formal annulation reactions, such as [2 + 1] and [4 + 1] annulation reactions. 9 Recently, a few reports involving ammonium ylide-mediated synthesis of substituted 2,3-dihydrobenzofurans have appeared in the literature. Almost all the reports on ammonium ylide-mediated synthesis of 2,3-DHBs comprise quinone methide as one of the reacting synthons.…”