Spirocyclopropane represents a privileged structural scaffold for accessing synthetic libraries of densely functionalized spirocarbo- and heterocyclic compounds. Due to the ubiquity of spirocyclic motifs as a potent pharmacophore in natural products and pharmaceuticals, recent years have witnessed significant advances in developing synthetic strategies that exploits carbon–carbon bond scission in spirocyclopropanes. This paper summarizes the recent developments in stereoselective ring expansion of spirocyclopropanes in diversity-oriented synthesis and highlights the synthetic as well as mechanistic rationale of those methodologies. This review also encompasses the applicability of the protocols in bioactive natural product syntheses.

Tandem C–N bond formation for the oxidative annulation of indolines with aziridines is accomplished employing the combination of DDQ and NaOCl at ambient conditions. Optically active aziridine can be coupled with high enantiomeric purity (>99% ee). The substrate scope, stereocontrol with the enantioenriched substrate, and scale-up are the important practical advantages.

Transition-metal-aided stereoselcetive construction of sp3-carbon-rich heterocyclic scaffolds using strained ring systems have received considerable attention in recent years due to their prominent presence in myraids of natural products, bio-active molecules...

Transition-metal-catalyzed CÀ H functionalization is one of the fascinating scientific fronts in organic synthesis for the formation of conjugated arenes and has emerged as a benchmark to revolutionize the synthetic enterprise since past decades. In this realm, chelationguided functionalization of CÀ H bonds using an exogenous directing group has received considerable attention recently for the expedient regioselective construction of CÀ C and Cheteroatom bonds as an efficient and sustainable alternative. This article outlines our contribution towards a wide variety of transformations that have been achieved by the directed CÀ H functionalization through the fine tuning of catalytic systems.

An iron(iii)-catalyzed [3+3]-annulation of bicyclic diaziridines and N-alkyl aziridines is developed for the synthesis of functionalized [1,2,4]-triazines. Ample substrate scope, functional group diversity, synthetic applications and enantiospecificity are the important practical features.