A highly efficient one-pot transformation of readily accessible furans into 4-hydroxy-2-cyclopentenones in H2O, using singlet oxygen as oxidant, has been developed.

A highly adaptable method targeting the ubiquitous and very important pyrrolizidine and indolizidine scaffolds is presented. The general synthetic utility of the method is underscored by its application to the rapid and easy synthesis of five natural products starting from readily accessible alkylfuran precursors. These unprotected primary furylalkylamines are subjected to photooxygenation conditions, which initiate a complex cascade reaction sequence concluding with the production of high value motifs. This sequence can be tailored to need by varying the choice of both photosensitizer and base additive.

Asymmetric and site-selective formal [3 + 2]-annulations of γ-alkyl-β,γ-unsaturated γ-lactams with α,β-unsaturated aldehydes have been developed. These organocatalysed transformations yield high value enantioenriched bicyclic γ-lactams with up to four new stereocenters (sometimes including a quarternary carbon). The overall transformation starts from simple and readily accessible furans and oversees a rapid, controlled, and dramatic enhancement in 3D complexity.

Pyrrolin-2-ones are a lesser known tautomeric relative of the 3-pyrrolin-2-ones. Despite their infrequent appearance in the literature, they are very interesting and useful compounds. They have highly controllable, multisite and multitype reactivities which are covered in this review. The applications of these transformations show how the 4-pyrrolin-2-ones make excellent intermediates en-route to a range of key alkaloids. Innovative, fast and adaptable syntheses of the 4-pyrrolin-2-ones and their onward use via cascade reaction sequences are also presented to complete the case for commending these compounds as highly versatile and valuable synthetic building blocks.

A general, flexible and highly effective method for the regio-, diastereo- & enantioselective one-pot synthesis of important carbocycles, namely, enantiopure cyclopentanones and their hydrindane congeners is presented.