153171-79-0Relevant academic research and scientific papers
Highly stereoselective cationic cyclization assisted by a sulfenyl group, scope, limitation, and mechanism
Liu, Changqing,Kudo, Kazuaki,Hashimoto, Yukihiko,Saigo, Kazuhiko
, p. 494 - 502 (2007/10/02)
When 8-acetoxy-2-naethyl-9-(phenylthio)-2-nonene (la) was treated with an acid, followed by a base, alkylative cyclization proceeded to give a mixture of 1,2-disubstituted cyclohexanes: 2a, 3a, and 4a. The stereochemistry of the reaction was only slightly affected by the leaving group and the reaction conditions, such as the temperature, solvent, and acid. However, the bulkiness of the sulfenyl group had a great effect on the stereochemical course of the reaction. High trans selectivity was attained when 1c (a derivative of 1a with a bulkier sulfenyl group) was used as a substrate. On the other hand, the length and rigidity of the carbon chain of the substrate also had a major effect on the stereochemistry of the reaction; a high cis selectivity was observed when 10a (a one-carbon-fewer analog of Ia) or 15a (a derivative with one more double bond in the carbon chain than in 1a) was used as the substrate. The reaction proceeded via a 6,5- or 5,5-fused-ring intermediate. The sulfenyl-group-assisted reaction could be a useful method for the stereoselective cyclization of acetates of α-sulfenylated secondary alcohols.
