64586-57-8Relevant academic research and scientific papers
A new efficient route to 2-substituted azulenes based on sulfonyl group directed lithiation
Shibasaki, Toshihisa,Ooishi, Takeo,Yamanouchi, Nobuhiko,Murafuji, Toshihiro,Kurotobi, Kei,Sugihara, Yoshikazu
, p. 7971 - 7977 (2008/12/22)
(Chemical Equation Presented) Directed lithiation of p-tolyl 1-azulenyl sulfone (1) at the 2-position of the azulenyl group was achieved by using lithium 2,2,6,6-tetramethylpiperidide (LTMP). The azulenyllithium thus generated could be efficiently trapped with various electrophiles to form 2-substituted derivatives 2 in moderate to good yields. p-Tolyl 2-trimethylsilyl-1-azulenyl sulfone (2a) was transformed into cyclic sulfone derivative 3a through the directed lithiation in the p-tolyl group and subsequent intramolecular ring closure at the 8-position. 2-(Phenylsulfanyl)-1-azulenyl p-tolyl sulfone (2b) suffered from desulfonylation to form 2-phenylsulfanylazulene (4). The Suzuki coupling reaction of 2-iodo-1-azulenyl p-tolyl sulfone (2d) with arylboronic acids followed by desulfonylation efficiently gave 2-arylazulenes 10.
