Wu Y, Wu X, Liu L, Yu JT, Pan C. Photocatalytic Carbosulfonylation/Cyclization of
N-Homoallyl and
N-Allyl Aldehyde Hydrazones toward Sulfonylated Tetrahydropyridazines and Dihydropyrazoles.
Org Lett 2024;
26:122-126. [PMID:
38160407 DOI:
10.1021/acs.orglett.3c03733]
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Abstract
N'-Benzylidene-N-homoallylacetohydrazides were designed and synthesized as novel skeletons for the construction of functionalized tetrahydropyridazines. A series of aryl- and alkylsulfonylated tetrahydropyridazines were obtained in yields of up to 94% employing sulfonyl chlorides as the sulfonyl radical sources under visible-light irradiation. Besides, sulfonylated dihydropyrazoles were also produced from N-allyl-N'-benzylideneacetohydrazides. Mechanistic investigations indicated that both energy transfer and single electron transfer processes were involved in accomplishing the radical 6/5-endo-trig cyclization to the C═N bond.
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