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L-Telluracyclohexa-2,5-diene

Reactions of l-telluracyclohexa-2,5-dienes 21 have been little studied. When heated with HPF6 in acetic acid, compounds 21 eliminate dihydrogen and convert to tellurapyrylium salts 25. The yields (73-83%) are higher than those of the same reaction with the oxygen, sulfur, and selenium analogs of 21 (88MI2). [Pg.15]

The addition of telluride anion to l-(trimethylsilyl)penta-l, 4-diyn-3-ones apparently represents a general method for the preparation of 2-substituted l-telluracyclohexa-2,5-dien-4-ones 22 (92MI3). In actual fact, the reaction of l-(trimethylsilyl)-5-phenylpenta-l,4-diyn-3-one with telluride anion affords 22 (R1 = Ph, R2 = H) in 38% yield, whereas only 12% of this compound is attained in the reaction with l-phenylpenta-l,4-diyn-3-one (87JOC3662). [Pg.17]

Like other dicoordinate tellurium compounds, l-telluracyclohexa-2,5-dien-4-ones 22 smoothly add halogens (chlorine, bromine, and iodine) affording cr-telluranes 31 in rather high yields. When treated with a peroxy acid, compounds 22 form 1,1-diacetoxy derivatives 31 (87JOC2123). 1-Tellurapyranylidenomalondinitriles 30 undergo similar transformations. [Pg.19]

According to X-ray structural data (92MI3), l-telluracyclohexa-2,5-dien-4-one is planar. No substantial intermolecular interaction between... [Pg.20]

A general method of synthesis of l-hetera-4-telluracyclohexa-2,5-dienes 90 is founded in the nucleophilic addition of telluride anion to type 91 diacetylene derivatives. The telluride dianion is prepared in situ from the elements in liquid ammonia. The reaction was carried out with methanol or mixtures with DMSO and liquid ammonia as solvents, with the following diacetylenes di(l-alkynyl)sulfides (73RTC1326), I-alkynylethynyl sulfides (75RTCI63), di(l-alkynyl)sulfones (78RTC244), and di(l-alkynyl)phosphi-noxides (75RTC92). [Pg.89]


See other pages where L-Telluracyclohexa-2,5-diene is mentioned: [Pg.1]    [Pg.15]    [Pg.15]    [Pg.16]    [Pg.17]    [Pg.32]    [Pg.1]    [Pg.15]    [Pg.15]    [Pg.16]    [Pg.17]    [Pg.32]   
See also in sourсe #XX -- [ Pg.15 , Pg.63 ]

See also in sourсe #XX -- [ Pg.15 , Pg.63 ]




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L-Telluracyclohexa-2,5-diene-4-ones

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