Dinuclear zinc catalyzed asymmetric [3 + 2] spiroannulation for the synthesis of diverse bispirocyclic saccharines

Abstract

An atom-economic asymmetric [3 + 2] spiroannulation reaction of saccharine-derived cyclic 1-azadienes with α-hydroxy-1-indanones has been developed via bimetallic cooperative catalysis. The developed synthetic strategy achieved through Michael/O-Mannich cascade process...

Annulations involving 1-indanones to access fused- and spiro frameworks

“…Very recently, an efficient synthesis of bispirocyclic saccharine system is realized involving asymmetric [3+2] spiroannulation reaction of saccharine-derived cyclic azadienes 167 with 2-hydroxy-1-indanones 163. 80 The bimetallic cooperative catalytic conversion was attributed via Michael/O-Mannich cascade process resulting highly stereoselective formation of bispirocyclic compounds 168 in which indanone, tetrahydrofuran, and saccharine moieties are embedded ( Scheme 46 ). 2-Hydroxy-1-indanones bearing electron-donating groups (Me, OMe) and electron-withdrawing groups (F, Cl, Br) underwent the [3+2] spiroannulation reaction with excellent enantioselectivity (up to 99% ee).…”

Stereoselective synthesis of Δ(1)-pyrroline sulfonamides via a chiral aldehyde mediated cascade reaction

“…1-Azadienes have been shown to be utility synthetic building blocks, particularly for building attractive heterocyclic scaffolds in domino reactions. 6–10 Herein, we present the results of the asymmetric cascade process of glycine as a C , N -1,2-dinucleophile (Nu 1 –Nu 2 ) with saccharine-derived cyclic 1-azadienes 7–10 catalyzed by a chiral aldehyde, providing an array of optically active Δ(1)-pyrroline derivatives bearing unsubstituted primary sulfonamide moieties in good yields with excellent stereoselectivities (Scheme 1, eqn (3)). It is worth noting that in this work we developed a new chiral aldehyde catalyst to implement our design.…”

Reversal of enantioselectivity by tuning the ring size of ProPhenol

“…32–42 The excellent performance of this ligand also attracted our attention. 43–49 In 2014, we reported the ProPhenol analogue ( S , S )- L 4 as a new addition to the chiral aza-crown family by replacing the prolinol moieties with chiral azetidines (Fig. 1C).…”