- Cationic Polar Cycloadditions of Phenylthionium Ions with Olefines: A New Route to Thiochromans
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Reaction of 2-chloro-N,N-dimethyl-2-(phenylthio)acetamide (1a) with styrene in the presence of stannic chloride gave 3,4-dihydro-N,N-dimethyl-4-phenyl-2H-1-benzothiopyran-2-carboxamide.The same benzothiopyran was also obtained from N,N-dimethyl-2-(phenylsulfinyl)acetamide and styrene under the Pummerer reaction conditions, but in lower yield.Similarly, α-chlorosulfides derived from ethyl 2-(phenylthio)acetate, 2-(phenylthio)acetonitrile, 1-(phenylthio)-2-propanone, and thioanisole reacted with styrene to give the corresponding 4-phenylbenzothiopyrans in variable yields.The reaction of 1a with trans-stilbene gave the expected benzothiopyran derivative, but the reaction of 1a with 1,1-diphenylethylene and phenylacetylene showed some variation of the reaction course.This cycloaddition reaction was extended to the intramolecular case.A possible mechanism for the formation of the benzothiopyran is discussed.
- Ishibashi, Hiroyuki,Okada, Motofumi,Sato, Kazumi,Ikeda, Masazumi,Ishiyama, Ko-ichi,Tamura, Yasumitsu
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- NUCLEOPHILIC SUBSTITUTION OF α-HALO-KETONES-XXII ACETOLYSIS OF α'-PHENOXY-α-CHLORO-KETONES. A COMPARISON OF THEIR REACTIVITY WITH THAT OF THE CORRESPONDING THIOETHERS
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The results obtained in the acetolysis of α-chloro-ketones 1 a-e are compared with those previously reported for the acetolysis of the corresponding α'-phenylthio-α-chloro-ketones 15a-e and discussed in terms of the enolization-solvolysis mechanisms.
- Pusino, A.,Rosnati, V.,Saba, A.
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p. 1893 - 1900
(2007/10/02)
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- REGIOSPECIFIC SYNTHESIS OF α-(PHENYLTHIO)CYCLOALKENONES AND OF α-PHENYL-α-(PHENYLTHIO)KETONES VIA αα-ADDITION OF PHENYLSULPHENYL CHLORIDE TO α-DIAZOKETONES
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Cyclic α-diazoketones react with phenylsulphenyl chloride at room temperature to furnish α-chloro-α-(phenylthio)cycloalkanones which undergo ready dehydrochlorination to α-(phenylthio)cycloalkenones when treated with triethylamine; acyclic, terminal α-diazoketones also furnish α-chloro-α-(phenylthio)adducts which are useful electrophiles in the synthesis of α-phenyl-α-(phenylthio)ketones.
- McKervey, M. Anthony,Ratananukul, Piniti
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p. 117 - 120
(2007/10/02)
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- NUCLEOPHILIC SUBSTITUTION OF α-HALO KETONES. XXI. STRUCTURE-REACTIVITY RELATIONSHIPS IN THE ACETOLYSIS OF 3-SUBSTITUTED 1-CHLORO-3-PHENYLTHIO-2-PROPANONES
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The acetolyses of α-chloro ketones 1a-d have been re-investigated under standard conditions and compared with those of the corresponding isomeric substrates 2a-d.It has been shown that participation by the neighbouring phenylthio group, involving a 1-3 shift of the latter, does occur in part even in the case of 1d, while it is the only process in the case of 1e.A few structure-reactivity relationships in the two series of substrates are discussed.
- Pusino, Alba,Rosnati, Vittorio,Saba, Antonio,Franco, Andrea
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p. 475 - 482
(2007/10/02)
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- PHOTOCHEMICAL RING CLOSURE OF α,α-BISULFENYLATED CARBONYL COMPOUNDS STEREOSELECTIVE FORMATION OF CIS-DIHYDROBENZOTHIOPHENES
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Photochemistry of α,α-bisulfenylated ketone has been investigated.Irradiation of 2-phenylthiodihydrothiophen-3-one (1) in benzene gave the radical recombination products 9 (63percent) and 10 (49percent).In a polar solvent, the ionic chemistry became predominant.Brief irradiation of 1 in acetonitrile and methanol gave the cis-fused dihydrothiophene 11 as the major product in 43percent and 20percent yields, respectively.The stereoselective photocyclization was generally observed for other ketones (2-8) in acetonitrile solution (Table 1).The photoproducts were easily dehydrated by treating with boron trifluoride etherate to give the corresponding benzothiophenes in high yields.Simple α-phenylthioketones are photoinert under the same conditions.The mechanism of this novel photocyclization of bisulfenylated ketones is also discussed.
- Sasaki, Tadashi,Hayakawa, Kenji,Nishida, Sumio
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- α-CETOALDEHYDES A GROUPEMENT ALDEHYDIQUE OU CETONIQUE PROTEGE
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α-Ketoaldehydes with protected ketogroup 2 or protected aldehydrogroup 3 are obtained by reaction of thiophenol or methanol with α-chloro-α-(phenylthio)aldehydes 7.
- Duhamel, Lucette,Chauvin, Joe,Messier, Angela
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p. 4171 - 4174
(2007/10/02)
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