Unusually Reactive and Selective Carbonyl Ylides for Three-Component Cycloaddition Reactions

Abstract

Conditions are described for the Rh-catalyzed formation of highly-functionalized dihydro-and tetrahydrofuran products via three-component reactions of aldehydes, α-alkyl-α-diazoesters, and dipolarophiles. The alkyl-substituted carbonyl ylides that are generated in this fashion are highly reactive in cycloaddition reactions, and display a scope of reactivity that is much broader than threecomponent reactions of carbonyl ylides derived from ethyl diazoacetate or α-aryl-α-diazoesters. The reactions of alkyl-substituted carbonyl ylides proceed with high regioselectivity and diastereoselectivity that are rationalized by an asynchronous, endo-selective transition state.

Modern Organic Synthesis with α-Diazocarbonyl Compounds

“…XXXX, XXX, XXX−XXX report described the formation of dihydro-and tetrahydrofuran products from three-component reactions (Scheme 276). 635 In terms of yield, the catalyst of choice for these reactions was Rh 2 (piv) 4 , although the catalyst did not affect the diastereomer ratio of the product.…”

Recent advances in the synthesis of tetrahydrofurans and applications in total synthesis

“…Coupling with an aldehyde leads to a 1,3-dipole intermediate that can react with a polarized olefin in a three-component reaction yielding 2,3,5-trisubstituted THF. 201 The scope of this reaction is limited to aromatic aldehydes, therefore the oxolanes obtained using this method have an aromatic substituent in position 2, and an electron-withdrawing group in positions 3 and 5 (Scheme 56). Further diastereocontrol can be obtained using a chiral oxazolidinone auxiliary as the electron withdrawing group.…”

Stereoselective Synthesis of Highly Functionalized Dispirooxindoles through [3+2] Cycloaddition of Carbonyl Ylides with 3‐Arylideneoxindoles

“…[10] Recently, 3-arylideneoxindoles were successfully utilized for the cycloaddition of azomethine ylides, [11] and pyridinium ylides.…”