Iodide-Mediated Synthesis of Spirooxindolo Dihydrofurans from Iodonium Ylides and 3-Alkylidene-2-oxindoles

Abstract

An iodide-mediated reaction between cyclic iodonium ylides of 1,3-dicarbonyls and 3-alkylidene-2-oxindoles results in 3H-spiro[furan-2,3'-indolin]-2'-ones. The reaction was tolerant to substitutions on both the alkylidene and ylide substrates and provided access to 19 new, densely functionalized polycyclic spirocycles in typically high yield.

Hypervalent iodine-mediated synthesis and late-stage functionalization of heterocycles

“…Later, Murphy's research team presented an unprecedented metal-free approach to access 3,3′spirooxindolo dihydrofurans 303 by reacting cyclic iodonium ylides 183 with 3-alkylidene-2-oxindoles 302 using Bu4NI catalysis (Scheme 81). 112 The reaction was tolerant to a variety of electron-poor and electron-neutral substituents on the alkylidene substrates and the products were isolated in high to excellent yields. Other iodonium ylides derived from 1,3-diketones, pyrimidines and 1,3-ketoesters smoothly gave spirocyclic products in significant yields.…”

Stereoselective synthesis and applications of spirocyclic oxindoles

“…A clearly distinct strategy to access this type of spirocycle is the use of hypervalent iodine reagents. 307 Building on the work of Gong for the synthesis of bispirooxindoles, 308 Du developed an enantioselective spirocyclisation using catalytic chiral hypervalent iodine reagent 96 with mCPBA as oxidant (Scheme 64). 309…”

Recent progress in the application of iodonium ylides in organic synthesis

“…However, iodonium ylides could behave as an electrophile in cycloaddition reactions at room temperature avoiding metal catalysts or photochemical activation. Murphy group 18 investigated Bu 4 NI-catalysed [3 + 2] cycloaddition of substituted 3-alkylidene-2-oxindoles 46 and iodonium ylide 16 for the synthesis of spirooxindolo dihydrofurans 47 (Scheme 9). The reaction tolerated both electron-rich and electron-poor oxindoles as well as keto, ester, and aryl substituents on the alkylidene.…”