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Naphthothiete und ihre Anwendung in der Heterocyclen‐Synthese
Author(s) -
Mayer Axel,
Rumpf Norbert,
Meier Herbert
Publication year - 1995
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.1995199512308
Subject(s) - chemistry
Naphtothietes and Their Application to the Synthesis of Heterocycles The three isomeric naphthothietes 5, 11 , and 16 were prepared according to the reaction sequences shown in Schemes 1–3. The final step was in each case a flash vacuum pyrolysis (FVP) of the corresponding mercaptonaphthalenemethanol 4, 9 , and 15 , respectively. The thiete rings in 5 and 11 can be opened by gentle heating; the ring opening of the isomer 16 possesses a much higher activation barrier. A MNDO calculation of the Δ H f values of 5, 11 , and 16 and the open isomers 5′, 11 ′, and 16 ′ provides an explanation for the different behavior. Photochemical ring opening represents a useful alternative. The reaction Schemes 4, 6, and 7 reveal the synthetic potential of the naphtho‐condensed thietes. Cycloaddition reactions with CC, CO, or CN double bonds lead into the series of differently condensed thiopyrans 17, 18, 24, 25, 26 , 3,1‐oxathiine 19 and 1,3‐thiazines 20, 21 .