13632-62-7Relevant articles and documents
Synthesis and photochromic behaviour of a series of benzopyrans bearing an: N -phenyl-carbazole moiety: Photochromism control by the steric effect
Adachi, Chihaya,Frigoli, Michel,Jousselin-Oba, Tanguy,Mamada, Masashi,Marrot, Jér?me,Ortica, Fausto,Pannacci, Danilo,Zangarelli, Agnese
, p. 1344 - 1355 (2020/11/03)
Five new N-phenyl-carbazole benzopyrans bearing different substitutions on one of the phenyl rings at the sp3 carbon have been synthesized. Their molecular structures were investigated by X-ray and NMR analyses and through quantum chemical calculations. T
Metal- and Acid-Free Methyl Triflate Catalyzed Meyer-Schuster Rearrangement
Yang, Lu,Zeng, Qingle
, p. 3149 - 3156 (2017/07/12)
A novel metal- and acid-free preparation of synthetically useful α,β-unsaturated carbonyl compounds from propargyl alcohols has been realized. This Meyer-Schuster rearrangement process is effectively catalyzed by methyl triflate (20 mol%) to prepare a broad scope of conjugated E -enals and E -enones generally in good to excellent yields (up to 90%). This reaction procedure operates under mild conditions (70 °C), in air, with short reaction times (1 h). Moreover, a carbocation intermediate trapped by the solvent 2,2,2-trifluoroethanol was isolated during this transformation.
Complementary iron(II)-catalyzed oxidative transformations of allenes with different oxidants
Sabbasani, Venkata R.,Lee, Hyunjin,Xia, Yuanzhi,Lee, Daesung
supporting information, p. 1151 - 1155 (2016/01/20)
Substituent- and oxidant-dependent transformations of allenes are described. Given the profound influence of the substituent on the reactivity of allenes, the subtle differences in allene structures are manifested in the formation of diverse products when reacted with different electrophiles/oxidants. In general, reactions of nonsilylated allenes involve an allylic cation intermediate by forming a C-O bond, at the sp-hybridized C2, with either DDQ (2,3-dichloro-5,6-dicyano-p-benzoquinone) or TBHP (tert-butyl hydroperoxide), along with FeCl2·4 H2O (10 mol %). In contrast, silylated allenes favor the formation of propargylic cation intermediates by transferring the allenic hydride to the oxidant, thus generating 1,3-enynes (E1 product) or propargylic THBP ethers (SN1 product). The formation of these different putative cationic intermediates from nonsilylated and silylated allenes is strongly supported by DFT calculations. Profound impact: Iron(II)-catalyzed transformations of allenes induced by either DDQ or tBuOOH depend on the substituent on the allenes. Nonsilylated and silylated allenes show complementary reactivity upon exposure to DDQ and tBuOOH in the presence of an iron(II) catalyst. Nonsilylated allenes incorporate the oxidant at the sp-hybridized carbon, whereas the silylated allenes generate 1,4-dehydrogenated 1,3-enynes. DDQ=2,3-dichloro-5,6-dicyano-1,4-benzoquinone.
