ChemInform Abstract: 2‐PHOSPHORYLATED TETRAHYDROPYRANS

Cycloaddition of hetarenesulfenyl chlorides to 3,4-dihydropyran

“…Reactions of 3,4-dihydropyran 1 with electrophilic reagents, including sulfenyl chlorides, usually lead to 1,2-addition products [1][2][3][4].…”

“…We have shown that the lithium perchlorate-nitromethane system stimulates polar cycloaddition of 2-chlorosulfenyl-1-pyridine-1-oxide (2), 3-methoxycarbonyl-2-pyridinesulfenyl chloride (3), and 4,6-dimethyl-2-pyrimidinesulfenyl chloride (4) at the multiple bond of the unsaturated ether 1, where ring closure occurs as a result of nucleophilic participation of the oxygen or nitrogen atom of the thiohetaryl moiety of the reagent to form tricyclic compounds 5-7. Judging from the 1 H NMR spectra, all the studied reactions occur regiospecifically and stereospecifically; in the spectra of compounds 5-7, the spin-spin coupling constant for the proton of the CHO moiety is in the range 2.5-5.1 Hz while the width of the signal from the proton of the CHS moiety (calculating from the outside peaks) is 14.0-18.6 Hz.…”