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

Abstract

Herein, we report the synthesis of π-conjugation-extended vinyl sulfoxonium ylides from vinyl sulfoxonium ylide and electrondeficient 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.

Stereoselective gem-Difunctionalization of Diazo Compounds with Vinyl Sulfoxonium Ylides and Thiols via Metalloradical Catalysis

“…Between these two carbene precursors, diazo compounds react faster under metal-catalyzed conditions than sulfoxonium ylides and generate a reactive electrophilic carbene intermediate, which is then trapped by sulfoxonium ylide as a nucleophile. Prompted by this observation and our continuing interest in sulfoxonium ylides, − we were intrigued to obtain stereoselective gem -difunctionalization of diazo compounds with the thiols and sulfoxonium ylides to obtain tertiary sulfide compounds, which are basic scaffolds for various natural products and medicinally important compounds. , …”

Catalyst-Controlled Divergent Synthesis of 2H-Chromenes via [3 + 3] Annulation of Vinyl Sulfoxonium Ylides with Quinones

“…Biosynthetically, 6-hydroxy-2 H -chromenes are obtained via oxa-6π electrocyclization of o -quinone methides (Scheme a) . Inspired by nature’s strategy, we hypothesized that treating vinyl sulfoxonium ylide at the α-position with quinone leads to o -quinone methide that can undergo oxa-6π electrocyclization to give 6-hydroxychromenes (Scheme b). One of the main challenges in achieving the objective is that the vinyl sulfoxonium ylide can undergo classical cyclopropanation with 1,4-naphthoquinone .…”

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

“…In continuation to our research interest in vinyl sulfoxonium ylides, 5 our group very recently reported that the addition of sulfoxonium ylides on ynoates produced dienyl sulfoxonium ylide, which is electronically similar to the aminodiene intermediate in the synthesis of pyridine. 6 We envisioned that, similar to the Bohlmann−Rahtz approach, in situ-generated dienyl sulfoxonium ylides can undergo intramolecular annulation to generate highly substituted arene in the absence of a catalyst or additive (Scheme 1b). However, there are two main challenges for this hypothesis: (i) Contrary to Bohlmann−Rahtz synthesis, which generates imine through thermodynamically feasible amine and keto condensation, the present reaction between sulfoxonium ylide and ketone in dienyl sulfoxonium ylide can result in epoxide rather than alkene (Scheme 1b, Step-2).…”

“…To investigate the mechanism for the [3 + 3] annulation, we performed the reaction of sulfoxonium ylide with ynone at 10 °C; the reaction yielded dienyl sulfoxonium ylide 8 which was confirmed by NMR and HRMS analysis (Scheme 4d). 6,15 This ylide 8 underwent annulation to give m-terphenyl adduct 3a at rt and gave paraben derivative 4a using TMSOTf. When we performed the reaction using keto-derived vinyl sulfoxonium ylide the reaction gave thiabenzene derivative 9.…”

“…The reaction proceeds via the Michael addition of enamines with ynones leading to an aminodiene intermediate that undergoes heat-induced E/Z isomerization, followed by cyclodehydration to yield substituted pyridines (Scheme a). In continuation to our research interest in vinyl sulfoxonium ylides, our group very recently reported that the addition of sulfoxonium ylides on ynoates produced dienyl sulfoxonium ylide, which is electronically similar to the aminodiene intermediate in the synthesis of pyridine . We envisioned that, similar to the Bohlmann–Rahtz approach, in situ -generated dienyl sulfoxonium ylides can undergo intramolecular annulation to generate highly substituted arene in the absence of a catalyst or additive (Scheme b).…”