862094-98-2Relevant academic research and scientific papers
Reductive elimination of phenylsulfonyl groups in the 3-position of benzo[a]heptalene-2,4-diols
Fattah, Mohy Eldin Abdel,El Rayes, Samir,Soliman, El Sayed Ahmed,Linden, Anthony,Abou-Hadeed, Khaled,Hansen, Hans-Juergen
, p. 1085 - 1101 (2007/10/03)
3-(Phenylsulfonyl)benzo[a]heptalene-2,4-diols 1 can be desulfonylated with an excess of LiAlH4/MeLi · LiBr in boiling THF in good yields (Scheme 6). When the reaction is run with LiAlH4/MeLi, mainly the 3,3′-disulfides 6 of the corresponding 2,4-dihydroxybenzo[a]heptalene-3- thiols are formed after workup (Scheme T). However, the best yields of desulfonylated products are obtained when the 2,4-dimethoxy-substituted benzo[a]heptalenes 2 are reduced with an excess of LiAlH4/TiCl 4 at - 78 → 20° in THF (Scheme 10). Attempts to substitute the PhSO2 group of 2 with freshly prepared MeONa in boiling THF led to a highly selective ether cleavage of the 4-MeO group, rather than to desulfonylation (Scheme 13).
