Regio- and stereoselective oxidation of unsaturated bicyclo[2.2.2]octanones with selenium dioxide
摘要:
The selenium dioxide oxidation of several unsaturated bicyclo[2.2.2]octanones has been examined in connection with the projected utility of properly functionalized products in tandem oxyanionic Cope rearrangement-S(N') transformations. The oxidations studied proved to be regioselective, with attack in the olefinic sector of each molecule occurring to the exclusion of chemical reaction alpha to the carbonyl. Stereoselectivity was also often encountered, with steric factors appearing to contribute heavily to establishing the particular configuration of the newly introduced stereogenic center.
Synthesis of the forskolin skeleton via anionic oxy-cope rearrangement
作者:Jeffrey A. Oplinger、Leo A. Paquette
DOI:10.1016/s0040-4039(00)96749-2
日期:1987.1
The forskolin prototype 14 has been elaborated in 9 steps from 2,4,4-trimethylcyclohexenone (5), the entire ring system materializing during oxyanionic Cope rearrangement of alcohol 10.
Forskolin: some stodies on ring B forming reactions
作者:Dirk Neunert、Harald Klein、Peter Welzel
DOI:10.1016/0040-4020(89)80095-x
日期:1989.1
Cyclization of the unsaturated sulfoxides 18b,18c underPummererconditions provided the six-membered products 20a and 21a, whereas base-catalyzed cyclization of the stereoisomeric epoxysulfones 16a,16b and 17a,17b led exclusively to the five-membered compounds 12a,12b and 15a,15b. The reaction 18b,18c → 20a,21a has been used to prepare the trans-decaline derivative 24 starting from the dimethylcyclohexenone
Towards the synthesis of polyoxygenated labdane diterpenes: Furan as building block for the C-ring
作者:Udo Lange、Winfried Plitzko、Siegfried Blechert
DOI:10.1016/0040-4020(95)00245-4
日期:1995.5
derivative 4 which is obtained by oxidative ring-opening of furfuryl alcohol 9. The three carbonyl groups of 11 are differentiated by the use of neighbour-group effects giving 12 which is transformed into the tricyclic compound 13 an interesting precursor for the synthesis of various labdanediterpenes.