Sulfur ylides first disclosed in 1930 have started to get more attention in 1960s, thanks mainly to the studies by Corey and Chaykovsky on their use for the preparation of...

The first stereoselective synthesis of enantioenriched axially chiral indole-quinoline systems is presented. The strategy takes advantage of an organocatalytic enantioselective Povarov cycloadditiono f3 -alkenylindoles and N-arylimines, followed by an oxidative central-to-axial chirality conversion process, allowing for access to previously unre-porteda xially chiral indole-quinoline biaryls. The methodology is also implementedf or the design and the preparation of challengingc ompounds exhibitingt wo stereogenic axes. DFT calculations shed light on the stereoselectivityo ft he central-to-axial chirality conversion,s howing unconventional behavior.Scheme1.Combining organocatalytice nantioselective Povarovc ycloadditions with the oxidative central-to-axial chirality conversion concept.

The 1,1a,2,7b-tetrahydrocyclopropa[ c ]chromene, arising from fusion of chromane and cyclopropane rings is the core of medicinally relevant compounds. Engaging sulfoxonium ylides in enantioselective aminocatalytic reactions for the first time, a convenient entry to this scaffold is presented. Several ring-fused derivatives were obtained in moderate-to-good yields and enantioselectivities and with perfect diastereoselectivity at the cyclopropane, using an α,α-diphenylprolinol aminocatalyst. The versatility of the hemiacetal moiety in the products was leveraged to effect various synthetic manipulations.

Funapide is a 3,3’‐spirocyclic oxindole with promising analgesic activity. A reported pilot‐plant scale synthesis of this chiral compound involves an asymmetric aldol reaction, catalyzed by a common bifunctional thiourea structure. In this work, we show that the swapping of the thiourea unit of the catalyst for a tailored squaramide group provides an equally active, but rewardingly more selective, catalyst for this aldol reaction (from 70.5 to 85 % ee). The reaction was studied first on a model oxindole compound. Then, the set of optimal conditions was applied to the target funapide intermediate. The applicability of these conditions seems limited to oxindoles bearing the 3‐substituent of funapide. Exemplifying the characteristics of target‐focused methodological development, this study highlights how a wide‐range screening of catalysts and reaction conditions can provide non‐negligible improvements in an industrially viable asymmetric transformation.

Stabilised sulfur ylides are synthetically appealing compounds, which reactivity under Brønsted acid catalysis has been poorly explored. Herein, we report a new catalyst‐ and substrate‐ dependent chemodivergent reaction between stabilised sulfur ylides and salicylaldehydes, leading to the (suprising) formation of 2H‐chromenes or dihydrobenzofurans products. Particular attention was set on the unusual mechanisms involved. Two unique reaction routes including two ylide units in the reactions are proposed. These pathways were validated by performing a selectivity switch in some cases, enabled by the modulation of the nucleophilicity of the sulfur ylide, and by the loading of the Brønsted acid catalyst in the reaction.