Phosphine-promoted intramolecular Rauhut-Currier/Wittig reaction cascade to access (hetero)arene-fused diquinanes

We describe the first phosphine-promoted intramolecular Rauhut-Currier reaction that triggers an intramolecular Wittig process assembling new classes of diquinanes. The one-pot strategy provides ready access to simple diquinanes and various (hetero)arene-fused diquinanes incorporated with up to two contiguous all-carbon quaternary centers under metal-free and neutral conditions. We showcased the generality of the method on a broad range of substrates and demonstrated its synthetic utility in accessing various advanced intermediates relevant to natural product synthesis and material science.

Photoredox-Catalyzed Synthesis of 3-Sulfonylated Pyrrolin-2-ones via a Regioselective Tandem Sulfonylation Cyclization of 1,5-Dienes

A mild, visible-light-induced, regioselective cascade sulfonylation-cyclization of 1,5-dienes with sulfonyl chlorides through the intermolecular radical addition/cyclization of alkenes C(sp²)-H was developed. This procedure proceeds well and affords a mild and efficient route to a range of monosulfonylated pyrrolin-2-ones at room temperatures.

Palladium-Catalyzed Carbonylative Synthesis of Polycyclic 3,4-Dihydroquinolin-2(1H)-one Scaffolds Containing Perfluoroalkyl and Carbonyl Units

A palladium-catalyzed one-pot two-step radical mediated carbonylative cyclization of 1,7-enynes with perfluoroalkyl iodides and Mo(CO)₆ has been developed for the construction of polycyclic 3,4-dihydroquinolin-2(1H)-one scaffolds. This method realizes a facile synthesis of various polycyclic 3,4-dihydroquinolin-2(1H)-one derivatives containing perfluoroalkyl and carbonyl units in high yields. Moreover, modifications of several bioactive molecules were demonstrated using this protocol.

Radical annulation using a radical reagent as a two-carbon unit

Radical annulation has emerged as one of the most efficient and straightforward methods for synthesizing cyclic/polycyclic compounds as the core structures can be constructed through a single procedure comprising multiple bond-forming steps. Particularly, radical annulation using a radical reagent as a cyclization partner and two-carbon unit greatly expands the diversity of cyclic skeletons and the functionality of radical reagents. We herein have highlighted the representative processes reported in the past decade for radical annulation using a radical reagent as a two-carbon unit, including [2 + 2 + 2], [3 + 2], [4 + 2], and [5 + 2] modes, with an emphasis on their reaction mechanisms. These studies not only pave the way toward annulation but also provide insight into the exploration of a new reaction mode for radical chemistry.

Copper-catalyzed construction of (Z)-benzo[cd]indoles: stereoselective intramolecular trans-addition and SN-Ar reaction

Substituted benzo[cd]indoles are one of the most attractive frameworks because of their wide range of biological and optical activities. Herein, a copper-catalyzed one-step synthesis of biologically important polysubstituted benzo[cd]indoles starting from 8-alkynyl-1-naphthylamine derivatives is reported. In this protocol, many substituents tolerated the reaction conditions and produced (Z)-benzo[cd]indoles in good yields. Preliminary mechanistic studies indicated that the reaction proceeds via a stereoselective intramolecular trans-addition and S_N-Ar reaction with high selectivity and high yields. The synthesized polysubstituted (Z)-benzo[cd]indoles possess sulfonamide building blocks, which make them candidates for bioactive molecules.