54736-49-1Relevant articles and documents
Irreversible E1cb Mechanism in the syn Eliminations from 1,2-Dihalogenoacenaphthenes Promoted by Potassium t-Butoxide in t-Butyl Alcohol
Baciocchi, Enrico,Ruzziconi, Renzo,Sebastiani, Giovanni V.
, p. 807 - 808 (1980)
The lack of a significant leaving group effect and the preferential departure of the "poorer" leaving group suggest an irreversible E1cb mechanism for the title reactions.
Ramberg-Baecklund Reaction of 1,3-Dibromo-1H,3H-naphthothiopyran 2,2-Dioxide. Formation of Acenaphthyne Intermediate
Nakayama, Juzo,Ohshima, Etsuo,Ishii, Akihiko,Hoshino, Masamatsu
, p. 60 - 65 (2007/10/02)
Radical bromination of 1H,3H-naphthothiopyran 2,2-dioxide (15) gave the corresponding monobromo sulfone 16 (48percent), dibromo sulfone 12 (43percent; cis/trans = 64/36), and tribromo sulfone 17 (5percent).Ramberg-Baecklund reaction of 12 was investigated under a variety of coditions with expectation of the formation of thiirene dioxide 11 from which generation of acenaphthyne (5) would be expected both thermally and photochemically.Observed characteristic features of the reaction are as follows: (i) the use of triethylamine as base yielded 1-bromo-acenaphthylene (20; 39percent) and debrominated products 15 (5percent) and 16 (9percent); (ii) the use of sodium methoxide as base afforded decacyclene (3) surprisingly, though in a trace amount, in addition to 20 (75percent) and acenaphthylene (18; 9percent); (iii) the use of potassium tert-butoxide as base gave an improved yield of 3 (5percent) along with 20 (36percent) and 18 (27percent).The formation of 3 may best be rationalized by assuming the generation of acenaphthyne intermediate 5 from 11 by loss of sulfur dioxide.
Concerted and Stepwise Mechanisms in the Eliminations from 1,2-Dihalogenoacenaphthenes Promoted by Potassium tert-Butoxide and Potassium Ethoxide in the Corresponding Alcohols
Baciocchi, Enrico,Ruzziconi, Renzo,Sebastiani, Giovanni Vittorio
, p. 3237 - 3241 (2007/10/02)
Anti and syn eliminations from cis- and trans-dihalogenoacenaphthenes, respectively, have been investigated in t-BuOK-t-BuOH and EtOK-EtOH.The leaving group ability order for the syn eliminations in t-BuOK-t-BuOH is F > Cl ca.Br, which suggests an (E1cB)I mechanism.Also consistent with this mechanism is the observation that from trans-1-chloro-2-fluoroacenaphthene only HF is eliminated.In EtOK-EtOH the order of leaving group ability for the syn eliminations is Br > Cl > F, which might suggest an E2 mechanism; however, the leaving group effects are very small, anda stepwise mechanism cannot be excluded.The anti eliminations from the cis-dihalogenoacenaphthenes exhibit a substantial leaving group effect; on this basis and also on considering the β-halogen effect on the rate of elimination, a concerted mechanism is suggested.
