We have developed a highly stereoselective formal [4+1] annulation reaction to construct trans-2,3-dihydrobenzofurans utilising in-situ generated supported pyridinium ylide. This approach has excellent substrate versatility, and gram-scale capability. Moreover, the...

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.

Heterocycles play an essential role in medicinal as well as in organic synthetic chemistry. The synthesis of these valuable scaffolds is an emerging and challenging field of today‘s research in organic chemistry. In recent years, several heterocycles as new synthons have emerged as potential nucleophiles in asymmetric transformations. Among them, 5H‐oxazol‐4‐one is one of the strategic synthons for synthesizing enantioenriched α‐alkyl‐α‐hydroxycarboxylic acid derivatives, which are otherwise very challenging via direct installation of a hydroxy group at the α‐position of carbonyls. Over the years, considerable progress has been made to establish new and efficient methodologies under mild reaction conditions exploiting metal‐ and organo‐catalysis. This review presents a comprehensive summary of various catalytic development in asymmetric synthesis employing 5H‐oxazol‐4‐ones as α‐alkyl‐α‐hydroxycarboxylic acid surrogates.

A facile approach to tri-substituted tetrahydrothiophenes via thia-Michael/aldol has been developed. The cascade reaction was carried out in the presence of 5 mol % of DABCO in ethyl acetate to...