Stereoselective Synthesis of Vinyl Triflones and Heteroaryl Triflones through Anionic O→C_vinyl and N→C_vinyl Trifluoromethanesulfonyl Migration Reactions

Abstract

Six transformations, one pot: Various di‐ and trisubstituted vinyl triflones, as well as several heteroaryl triflones, were stereoselectively synthesized from easily accessible gem‐dibromovinyl substrates (see scheme, Boc=tert‐butoxycarbonyl). The highlights of this synthetic method lie in the remote O→Cvinyl or N→Cvinyl triflyl migrations and the one‐pot, three‐step protocol.

Cs2CO3-Mediated Regio- and Stereoselective Sulfonylation of 1,1-Dibromo-1-alkenes with Sodium Sulfinates

“…K 2 CO 3 and Na 2 CO 3 (2 equiv) formed 3a in 60% and 45% yield, respectively; meanwhile, the reactions with CsF, Et 3 N, NaOAc, and KOt-Bu produced 3a in low-to-moderate yields (Table 1, entries 7-12). The screening of the solvents indicated that DMF yielded 78% 3a along with 10% 4a, whereas toluene, MeCN, and 1,4-dioxane did not yield any products (entries [13][14][15][16]. Note that the reaction did not occur below 100 °C.…”

“…14 A stereoselective synthesis of vinyl triflones starting from gem-dibromovinyl derivatives has been achieved via triflyl migration reactions. 15 Although the synthesis of vinyl sulfones has been widely and intensively studied, the synthesis of 1-bromo-1-sulfonylalkenes has been shown only in few reports. For instance, sulfonylation of activated alkynes with sodium sulfinates, 16 as well as sulfinic acids 17 in water as the reaction medium have been developed.…”

Palladium‐Catalyzed Domino Cyclization/Phosphorylation of gem‐Dibromoolefins with P(O)H Compounds: Synthesis of Phosphorylated Heteroaromatics

“…In recent years, gem-dihaloolefins have been recognized as a type of useful starting material for the synthesis of functionalized heteroaromatics, meanwhile, diverse functional groups can be introduced in one step. [8][9][10][11][12] The groups of Lautens, [9] Wang, [10] Alper [11] and others [12] have realized transition-metal-catalyzed tandem cyclization/functionalization of gem-dihaloolefins with various nucleophiles, which afforded C2-halogenated, (hetero)aryled, alkenyled, alkynyled, cyanated, trifluoromethylthiolated(selenolated), and carbonylated benzofused heterocycles. In 2004, Bisseret and coworkers [8g] reported a palladium-assisted cyclization/ phosphorylation of gem-dibromoolefins with diethylphosphonate for synthesizing C2-phosphorylated benzofuran or indole.…”

Electrophilic Triflyl-arylation and Triflyl-pyridylation by Unsymmetrical Aryl/Pyridyl-λ3-iodonium Salts: Synthesis of Aryl and Pyridyl Triflones

“…Several methods such as the use of trifluoromethanesulfonylating (triflylating) reagents, oxidation of corresponding trifluoromethylthio aromatic compounds, transformation from SO 2 CF 3 -containing building blocks, and intramolecular rearrangements have been developed over the years . Despite this, methods for nucleophilic substitution on an Ar-SO 2 CF 3 motif, the S N Ar reaction, remain challenging due to the electrophilic nature of sulfone, giving rise to regioselectivity issues.…”