A novel approach to the synthesis of (±)-fragranol is described that relies on a radical 4-exo cyclization. This key step is catalyzed by a cationic titanocene complex with a pending amide ligand. In this manner the radical and its acceptor are bound to the titanocene center in a two-point mode. By this interaction the 4-exo cyclization that is not supported by gem-dialkyl substitution is rendered
Stereospecific palladium(0)-catalyzed reduction of 2-cyclobutylidenepropyl esters. A versatile preparation of diastereomeric monoterpenoids: (±)-fragranol and (±)-grandisol
作者:Angela M Bernard、Angelo Frongia、Francesco Secci、Giovanna Delogu、Jean Ollivier、Pier P Piras、Jacques Salaün
DOI:10.1016/j.tet.2003.09.074
日期:2003.11
Mixtures of (E and Z)-2-cyclobutylidenepropyl sulfonates, readily available from alpha,alpha-disubstituted cyclobutanones arising from suitable cyclopropane derivatives ring expansion, underwent regioselective and stereospecific reduction by formate anion to offer, through pi-1, 1-trimethyleneallylpalladium complexes formed upon treatment with palladium(O), a new and convenient entry to the diastereomeric four-membered ring monoterpenoids (+/-)-fragranol and (+/-)-grandisol. (C) 2003 Elsevier Ltd. All rights reserved.
Kim, Deukjoon; Lee, Young Kyoung; Jang, Yoo Mi, Journal of the Chemical Society. Perkin transactions I, 1990, # 12, p. 3221 - 3224
作者:Kim, Deukjoon、Lee, Young Kyoung、Jang, Yoo Mi、Kim, In O、Park, Sang Woo