157604-03-0Relevant articles and documents
Stereoselectivity and Generality of the Palladium-Catalysed Cyclopropanation of α,β-Unsaturated Carboxylic Acids Derivatized with Oppolzer's Sultam
Vallaerda, Jerk,Appelberg, Ulf,Csoeregh, Ingeborg,Hacksell, Uli
, p. 461 - 470 (2007/10/02)
A series of α,β-unsaturated carboxylic acids derivatized with camphorsultam 1 a s a chiral auxiliary has been stereoselectively cyclopropanated. the selectivity of the reaction produces cyclopropanated products with the 1R,2R absolute configuration as indicated by the optical rotations as well as by an X-ray structure determineation.The temperature dependence of the reaction was studied with three substrates. the highest stereoselectivity was obtained at temperatures above 25 deg C.Branching at the α- or β-carbons disfavours complete conversion, and electron-withdrawing substituents at these positions seem to prevent the reaction.The auxiliary was removed by using titanium(IV) isopropoxide in benzyl alcohol followed by alkaline hydrolysis of the intermediate ester. the potent 5-HT1A receptor agonist (1R,2S)-2-(2-hydroxyphenyl)-N,N-dipropylcyclopropylamine 13 was synthesized by this method