Derivatives of 1,4‐Naphthoquinone via 3‐(Phenyliodonio)‐1,2,4‐trioxo‐1,2,3,4‐tetrahydronaphthalenide

Abstract

The title compound 3 reacts with various electrophiles such as hydrogen halides, benzoyl chloride, iodomethane, and bromine to afford 3‐halo derivatives of 2‐hydroxy‐1,4‐naphthoquinone. 3 reacts also with dimethyl sulfide to give a trans‐ylidation product; photochemically, furan derivatives are formed with 2‐methyl‐2‐butene, styrene, and phenylacetylene. Carbon disulfide affords the 2‐thioxo‐1,3‐oxathiole derivative 15.

Styryl and functionalized aryl derivatives of lawsone through metal-free cross-coupling of its BF3-activated phenyliodonium ylide with cinnamaldehydes and arylaldehydes

“…On the other hand, the intermediacy of a crowded, as shown by 3D molecular models, complex like 22 (Scheme 10), which, through a process analogous with the above suggested (Scheme 9), leads subsequently to biradical 23 and by loss of PhI to the formate 24 and finally to 13c-g, is not considered very likely because it could not rationalize the observed stereospecificity of the isolated products. The relatively high level of stereospecificity could be better explained by a mechanism involving mediation of a carbene, whose electrophilicity is enhanced by the coordination of BF 3 with the adjacent carbonyls (25). Being activated, carbene intermediate 25 undergoes electrophilic attack by the relatively inactivated C]C bond of cinnamaldehyde, leading through cyclopropanation (26) to the formate 24 and by subsequent hydrolysis to the final products 13c-g (Scheme 10).…”

“…The outcome of the analogous photochemical reactions was similar. 25 Through this process of iodonium group substitution, the formation of aryl-hydroxynaphthoquinones is also facilitated. Stagliano accomplished the arylation of lawsone and its derivatives through a Stille-type coupling reaction of their phenyliodonium ylides with arylstannates (Scheme 1).…”

Hypervalent Iodine–Mediated Ring Contraction Reactions

“…It is worth mentioning that this approach can be used for the synthesis of five-, six-, and seven-membered ring derivatives, as shown in Scheme 7 and 8. A two-step procedure to promote the ring contraction of 2-hydroxy-1,4-benzoquinones to 2-cyclopentene-1,4-diones has been developed by the group of Varvoglis and co-workers [25,26]. This approach is based on the thermolysis of a phenyliodonium species, which is obtained by reaction of a hydroxyquinone with iodobenzene diacetate.…”

Hydroxyquinones: Synthesis and Reactivity

“…As it was already mentioned, iodonium ylides of hydroxy quinones offer interesting synthetic possibilities. These ylides are prepared in good yields from the reaction of hydroxybenzo-or naphthoquinones with (diacetoxyiodo)benzene [70,71] (Scheme 62) .…”

“…Iodonium ylides are labile compounds, react with both electrophiles and nucleophiles and afford cyclization products under photochemical conditions, as illustrated in Scheme 63 [70]. Especially noteworthy is the thermal ring contraction to indandione in high yield.…”