A. Hofmann, Rui Ren, A. Lough
Apr 10, 2006
Citations
0
Influential Citations
2
Citations
Journal
Tetrahedron Letters
Abstract
Abstract 1,3,5-Tris(bromomethyl)-1,3,5-trialkylcyclohexanes (alkyl = methyl, n -propyl) were prepared. These are the first examples of 1,3,5-tris(halomethyl)-1,3,5-trialkylcyclohexanes. One synthetic method directly converted the corresponding triols with PPh 3 Br 2 , where an excess of the bromination reagent and high temperature (175 °C) were required. Stoichiometric use of PPh 3 Br 2 under mild conditions, successfully employed for the synthesis of the parent tris(bromomethyl)cyclohexane, did not lead to the desired tribromides but rather to cyclic ethers. Proximity effects triggered by the 1,3,5-alkyl groups strongly influence the reactivity of such highly substituted cyclohexanes. An alternative synthetic access to the tris(bromomethyl) compounds was also developed, using 1,3,5-tris(triflatomethyl)-1,3,5-trialkylcyclohexanes (triflato = F 3 CSO 3 ) as synthetic intermediates. An X-ray crystal structure of 1,3,5-tris(bromomethyl)-1,3,5-trimethylcyclohexane was obtained.