The synthesis and properties of 6-trifluoromethyl-substituted thiopyrano[3,4-d]isoxazole derivatives

Concise Synthesis of 7-Deoxypsammaplysins K and O and 7-Deoxyceratinamide A by 1,3-Dipole Cycloaddition

“…We then decided to couple the spirooxepin isoxazoline motif with the side chains (see Supporting Information) of psammaplysins K (1) and O (2) to synthesize their C7deoxyl-spiro-oxepin isoxazoline-based products. Ester 13 was treated with a solution of LiOH•H 2 O in H 2 O at 0 °C, and the resultant acid, which was unstable, 28 was immediately coupled with p-nitrophenylamine (15) in the presence of Nmethylimidazole and N,N,N′,N′-tetramethylchloroformamidinium hexafluorophosphate 29 to give amide 16 in 43% yield. The structure of 16 was confirmed by X-ray crystallographic analysis (Scheme 2).…”

Update on thiopyran-fused heterocycle synthesis (2013–2024)

“…The synthesis of thiopyrano[3,4- d ]isoxazole-3-carboxylates 284 was accomplished by Siryi and coworkers by the [3 + 2] cycloaddition of ethyl cyanocarboxylate N -oxide 282 and 6-trifluoromethyl-2 H -thiopyran 283 (Scheme 53). 83 On treatment of 284 with zinc in acetic acid, a mixture of diastereomeric lactones 286 and 287 was obtained, probably via α-acetylaminoester intermediate 285 by intramolecular cyclization and CN reduction.…”

Trifluoromethylated Thiopyranoid Glycals: Synthesis and Ferrier (I) Type Reactions

“…According to the proposed Scheme Ferrier product 13 is an initial kinetically controlled product of the reaction between methanol and chloride 8 as well as with diacetate 7. When strong acid (HCl or TsOH) is present, compound 13 rearranges to thermodynamically more stable 4-methoxy-3,4-dihydro-2H-thiopyran (15). The latter undergoes acid-catalyzed deacetylation giving 3-hydroxy derivative 9, which is converted to dimethoxy tetrahydrothiopyran derivative 10.…”

“…[7,8] In contrast, Ferrier (I) reactions of glycal analogs with sulfur in the ring remain practically unknown, with rare exception. [9,10] With the aim to extend the scope of this reaction and as a part of our ongoing work on the chemistry of fluorinated thiopyran derivatives, [11][12][13][14][15] we focused on the polyfluoroalkylated thiopyranoid glycal analogs (Figure 1, X = S, R 2 = R F ). Besides being synthetically challenging structures of academic interest, they seem potent substrates for Ferrier (I) reaction.…”