Synthesis of the benzo[b]fluorene core of the kinamycins by cycloaromatization of non-conjugated benzotriynes

Tetrahedron Letters

Volumn 40, Issue 43, 1999, Pages 7701-7704

  Rodríguez, David ^a   Castedo, Luis ^a   Domínguez, Domingo ^a   Saá, Carlos ^a  

^a UNIVERSITY OF SANTIAGO DE COMPOSTELA   (Spain)

Author keywords

Benzo b fluorene; Enediynes; Enetriynes; Kinamycin; Radical cycloaromatization

Indexed keywords

ALKYNE DERIVATIVE; FLUORENE DERIVATIVE; KINAMYCIN;

AROMATIZATION; ARTICLE; CYCLIZATION; HEAT TREATMENT; PARTIAL DRUG SYNTHESIS;

EID: 0033595860     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(99)01570-1     Document Type: Article

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14. +, 27), 327 (45), 313 (50), 239 (93), 73 (100).
15. All new compounds gave satisfactory analytical and spectroscopic data.
16. +, 77), 327 (42), 239 (100), 73 (55).
17. 3 in MeOH at rt for 1 h.
18. 5 and o-iodoanisole in 82% yield.
19. A similar 1,4-biradical has been assumed to be involved in the cycloaromatization of 1,6,11-dodecatriyne, see: Kociolek, M. G.; Johnson, R. P. Tetrahedron Lett. 1999, 40, 4141-4144.
20. 1H NMR of deuterated 3a does not show the singlet at 8.01 ppm due to H5.
21. When a benzotetrayne was used as starting material, the intermediate biradical species cycloaromatized with the alkyne to give an o-aryl biradical: see Ref. 6.