Stereoselective Synthesis of Five-Membered Spirooxindoles through Tomita Zipper Cyclization

Abstract

Functionalized five-membered spirooxindoles were furnished in good yields and excellent stereoselectivities by using an effective Tomita zipper cyclization (TZC) reaction through organophosphine catalysis.

Organocatalytic transformations of alkynals, alkynones, propriolates, and related electron-deficient alkynes

“…115 Recently, Ramachary and co-workers have described a versatile intramolecular zipper cyclization protocol for the stereoselective synthesis of substituted five-membered spirooxindoles 233 from but-3-yn-2-ones 231 and 3-alkylideneindolin-2-ones 232 (Scheme 100). 116 The novelty of this work was the synthesis of carbocycles by the reaction of buta-1,3-dien-2-olates generated by addition of phosphine to alkyne.…”

AgNO3‐Catalysed Intramolecular Cyclization: Access to Functionalized Cyclopentanones and Spiro‐Cyclopentanones

“…In addition, Siby in 2009 and Ramacharya in 2017 established reaction via activated alkyne using MePh 2 P to form substituted cyclopentanones . Recently, Ramachary and co‐worker achieved the stereoselective synthesis of spirooxiindole via Tomita Zipper cyclization . Tomita et.al, Fu et.al, Siby et.al and Ramachary et.al demonstrated cyclization of alkyne in which phosphorus catalyst was used (Scheme ), which require longer reaction time with lower yields of the cyclized product.…”

Synthesis of Substituted Biaryls through Gold‐Catalyzed Petasis–Ferrier Rearrangement of Propargyl Ethers

“…In 2012, Shi developed the phosphine‐promoted synthesis of spiro[furan‐2,3′‐indoline]‐2′,4(5 H )‐diones by [3+2] annulations between N ‐protected isatins and but‐3‐yn‐2‐one 3. Rammchary and co‐workers described a phosphine‐catalyzed Tomiat–Zipper cyclization of methyleneoxindoles with 4‐phenyl‐but‐3‐yn‐2‐one for the synthesis of spiro[cyclopentane‐1,3′‐oxindoles] 4. In 2012 Chuang and co‐workers reported a convenient route for the synthesis of aryl‐substituted γ‐lactones bearing an α‐phosphorus ylide moiety through the assembly of dimethyl acetylenedicarboxylate, electron‐deficient aldehydes, and triaryl‐ or trialkylphosphanes 5.…”