Insights into the temperature-driven competitive pericyclic transformations of allyloxy furan.

Here, using comprehensive density functional theory calculations augmented by labeling studies, we investigated the mechanistic details of low temperature [3,3]-sigmatropic rearrangement reaction of allyoxy furan and its [4+2]-cycloaddition reaction with acetylene dicarboxylate. In particular, we identify important factors contributing to the low energy requirement of the [3,3]-sigmatropic rearrangement reaction.

Computational exploration of vinyl sulfoxonium ylide chemistry.

This review comprehensively examines the computational techniques employed to elucidate the reactivity, selectivity, and mechanistic pathways of vinyl sulfoxonium ylides. By delving into a spectrum of reactions ranging from insertion and cycloaddition to annulation, multicomponent reactions, and carbene-mediated transformations, we demonstrate the pivotal role of computational techniques in understanding the mechanism, reactivity and selectivity. The synergy between experimental and computational approaches is emphasized as a driving force for future breakthroughs and the continuous evolution of this dynamic and emerging field.

Ylide-Induced Ring Contraction of Coumarins to Benzofurans: Applications to the Synthesis of -Heterocycles.

We report an unusual ring contraction of 4-chlorocoumarin to benzofuranoyl sulfoxonium ylides using a Corey-ylide. These stabilized ylides were subsequently utilized for the synthesis of various valuable -heterocycles under both metal and metal-free conditions. The synthetic utility of this method is illustrated through the synthesis of known bioactive compounds.

Nucleophilic Dearomatization of Activated Pyridines Using Vinyl Sulfoxonium Ylides: Application to the Synthesis of -Heterocycles.

A highly efficient method has been developed for synthesizing 4-dienyl dihydropyridines through the nucleophilic dearomatization of activated pyridines using vinyl sulfoxonium ylides. This reaction follows the sequence involving ylide addition to activated pyridine, [2,3]-sigmatropic rearrangement, and subsequent sulfenic acid elimination. The resulting 4-dienyl dihydropyridines are then used in the synthesis of highly substituted -heterocyles.

Diastereoselective cyclopropanation of α,β-unsaturated carbonyl compounds with vinyl sulfoxonium ylides.

Herein, we report a three-component stereoselective cyclopropanation of vinyl sulfoxonium ylides with indane 1,3-dione and aldehydes under mild reaction conditions. In contrast to previous reports, the present work shows that electrophilic addition selectively takes place at the α-position of the vinyl sulfoxonium ylide. The interesting feature of this approach is that the multicomponent reaction selectively proceeds because of the difference in nucleophilic reactivity of vinyl sulfoxonium ylides and indane 1,3-dione with electrophilic partners, such as aldehydes and generated arylidenes.

Visible Light-Promoted Regioselective Benzannulation of Vinyl Sulfoxonium Ylides with Ynoates.

Herein, we report a highly regioselective [4 + 2]-annulation of vinyl sulfoxonium ylides with ynoates under light-mediated conditions. The reaction proceeds through the new dienyl sulfoxonium ylide, which undergoes photolysis under blue light irradiation to give highly substituted naphthalene scaffolds. The method presented here operates at room temperature and does not require the addition of an external photosensitizer.

Carbene-mediated stereoselective olefination of vinyl sulfoxonium ylides with diazo compounds and acetals.

The development of stereoselective olefination using sulfur ylide-derived vinyl carbenes with diazo esters and acetals is reported. Both reactions proceed through nucleophilic addition to electrophiles at the γ-position of an -generated 2-alkoxy furan intermediate. The synthetic utility of the developed method is demonstrated by the total synthesis of rubrolide E.

Divergent Approach to Highly Substituted Arenes via [3 + 3] Annulation of Vinyl Sulfoxonium Ylides with Ynones.

Herein, we report the divergent benzannulation for highly substituted arenes using vinyl sulfoxonium ylides and ynones. The addition of ynone at the γ-position of vinyl sulfoxonium ylides leads to dienyl sulfoxonium ylide that can undergo selective annulation under different conditions to give -terphenyls and parabens. Moreover, control experiments and quantum chemical calculations reveal two distinct reaction mechanisms for both annulations.

Synthesis and Applications of π-Conjugation-Extended Vinyl Sulfoxonium Ylides.

Herein, we report the synthesis of π-conjugation-extended vinyl sulfoxonium ylides from vinyl sulfoxonium ylide and electron-deficient alkynes. The new dienoate ylides are used in various transformations, such as X-H (X = S, O) insertion, halogenation, carbene-mediated transformation, and radical-mediated reductions to obtain a variety of conjugated dienoates.

Ir(I)-Catalyzed Synthesis of Furanones from Vinyl Sulfoxonium Ylides.

A method for the synthesis of allyl substituted γ-butenolides via carbonyl ylide rearrangement of vinyl sulfoxonium ylide-derived carbenes has been developed. At rt, the mechanism involves a carbonyl ylide generation/allyloxy furan formation/[3,3]-sigmatropic rearrangement/isomerization sequence for the generation of 3-allyl butenolides. At 70 °C, instead of the final isomerization step, the resulting [3,3]-sigmatropic rearrangement product undergoes further [3,3]-sigmatropic rearrangement to produce 5-allyl butenolide.

Bidirectional Iterative Approach to Sequence-Defined Unsaturated Oligoesters.

Herein, we describe the development of a new strategy for the synthesis of unsaturated oligoesters sequential metal- and reagent-free insertion of vinyl sulfoxonium ylides into the O-H bond of carboxylic acid. Like two directional coupling of amino acids (N- to C-terminal and C- to N-terminal) in peptide synthesis, the present approach offers a strategy in both directions to synthesize oligoesters. The sequential addition of the vinyl sulfoxonium ylide to the carboxylic acids (acid iteration sequence) in one direction and the sequential addition of the carboxylic acids to the vinyl sulfoxonium ylide (ylide iteration sequence) in another direction yield (Z)-configured unsaturated oligoesters.

Ru-Catalyzed Benzannulation of Vinyl Sulfoxonium Ylide with Electron-Deficient Alkynes and Alkenes.

Herein, we report carbene-mediated benzannulation of vinyl sulfoxonium ylides with electron-deficient alkynes and alkenes to synthesize oxygenated arenes. This protocol features excellent regioselectivity, a broad substrate scope, and mild reaction conditions. Mechanistic studies revealed that the reaction proceeds through furan generation, cycloaddition, ring cleavage, and aromatization cascades.