Catalytic Asymmetric Synthesis of Chiral Spiro‐cyclopropyl Oxindoles from 3‐Alkenyl‐oxindoles and Sulfoxonium Ylides

Abstract

A new enantioselective cyclopropanation of 3-alkenyl-oxindoles with sulfoxonium ylides was realized by using a chiral N,N'-dioxide/Mg(OTf) 2 complex as the catalyst. Various chiral spiro-cyclopropyl oxindoles containing two or three continuous chiral carbon centres were obtained in high yields (up to 99%) with good dr (up to 97:3 dr) and high ee values (up to 94% ee).

Copper‐Catalyzed Dimerization of Sulfoxonium Ylides with 3‐Diazoindolin‐2‐imines: A Practical and Efficient Approach to Spiro[cyclopropane‐1,3′‐indolin]‐2′‐imines

“…Based on our observations and Feng′s work, we proposed a possible mechanism for the formation of 3 (Scheme ). In the first step, copper carbene intermediate A isformed from 1a .…”

“…More recently, Feng and co‐workers reported a cyclopropanation of 3‐ alkenyl‐oxindoles with sulfoxonium ylides and obtained a range of spirocyclopropyl oxindoles (Equ. 2, Scheme ) . Previously, we reported an efficient rhodium catalyzed cyclopropanation of 3‐diazoindolin‐2‐imines with olefins, to provide spiro[cyclopropane‐1,3′‐indolin]‐2′‐imines with high diastereoselectivity (Equ.…”

Asymmetric transformations from sulfoxonium ylides

“…In 2018, Feng and co-workers disclosed a new enantioselective cyclopropanation of 3-alkenyl-oxindoles with sulfoxonium ylides. 106 In contrast to all of the previous papers, the authors were able to use keto sulfoxonium ylides over the simple DMSM (Scheme 14B). 106 Using a combination of chiral N,N'-dioxide ligand (103) and Mg(OTf) 2 as catalyst, 25 spirocyclopropyl oxindoles (104) were obtained in good yields (61-99%), excellent dr (up to 97:3 dr) and good to excellent enantiomeric excesses (66-94% ee).…”

“…106 In contrast to all of the previous papers, the authors were able to use keto sulfoxonium ylides over the simple DMSM (Scheme 14B). 106 Using a combination of chiral N,N'-dioxide ligand (103) and Mg(OTf) 2 as catalyst, 25 spirocyclopropyl oxindoles (104) were obtained in good yields (61-99%), excellent dr (up to 97:3 dr) and good to excellent enantiomeric excesses (66-94% ee). Interestingly, when the authors used DMSM as ylide source under the reaction conditions, the cyclopropane product was formed in only 35% yield and 57:43 dr (16% ee and 5% ee, respectively).…”

Syntheses and Applications of Spirocyclopropyl Oxindoles: A Decade Review

“…Feng and co‐workers featured the utility of sulfoxonium ylides 26 in N,N' ‐dioxide I /Mg(OTf) 2 catalyzed asymmetric synthesis of spirocyclopropyl oxindoles 27 (Scheme 6). [ 18 ] The use of DMAP ensured improved diastereoselectivity. On the other hand, use of other metal triflates such as Ni, Zn, etc.…”