82187-14-2Relevant academic research and scientific papers
Medium-ring Ketone Synthesis. Intramolecular Acylation of Sulfur-stabilized Carbanions: A Model Study
Ohtsuka, Yasuo,Oishi, Takeshi
, p. 443 - 453 (2007/10/02)
Intramolecular acylation of the sulfur-stabilized carbanions of the acyclic ester 9 and amide sulfides 11 was carried out as a model study for developing an effective method for the construction of medium-ring ketones by ring closure.Reaction of 9a-c or 11a-g with lithium diisopropylamide (LDA) proceeded smoothly and the expected keto sulfides 10a-c or 12a-g, respectively, were obtained.In the cases where R1 and/or R2 in 11 were normal alkyl groups, the reaction did not take place.However, these difficulties were readily overcome either by introducing a methyl group next to the carbonyl group or by converting the sulfides into the corresponding sulfoxides or sulfones.Acylation in the allyl sulfides 11b, d, f and the allyl sulfone 20b takes place at the α-position to the sulfur atom, yielding β,γ-unsaturated ketones.A reductive removal of the sulfide moiety or its conversion into other functional groups was also examined.
