General Methodology for the Topologically Selective Preparation of Linear and Nonlinear Tricyclopentanoids of Hirsutane and Isocomene Type<i>via</i>a Claisen Rearrangement / Cyclopentene Annulation Sequence. Total Synthesis of (±)- Epiisocomene
作者:Tomas Hudlicky、Lawrence D. Kwart、Mark H. Tiedje、Brindaban C. Ranu、Robert P. Short、James O. Frazier、H. Lee Rigby
DOI:10.1055/s-1986-31756
日期:——
The intramolecular cyclopentene annulation methodology which combines the cyclopropanation of dienic diazoketones and the vinylcyclopropane rearrangement is utilized to synthesize linear tricyclopentanoids of the hirsutane class or nonlinear members of the isocomene class. The requisite diene precursors, endocyclic or exocyclic, respectively, are obtained from acylcyclopentenes via orthoester Claisen rearrangement of either allyl or propargyl alcohols. The scope and the generality of the method are indicated and experimental details are presented pertaining to the synthesis of precursory dienes for hirsutane and isocomene sesquiterpenes. Full details are disclosed concerning the total synthesis of epiisocomene and the synthesis of linearly fused precursors to coriolin sesquiterpenes.
Aluminum oxide catalyzed isomerization of acylated cycloalkenes
作者:T. Hudlicky、T. Srnak
DOI:10.1016/s0040-4039(01)81902-x
日期:1981.1
homologous series of cyclic olefins and their corresponding 1-methyl derivatives were acylated using acetic anhydride/zinc chloride system. The resulting mixtures were, after appropriate analysis, isomerized quantitatively to the conjugated enones by adsorption on neutral alumina. A detailed, general experimental procedure is given.
Thermolyse et photolyse de cétones non saturées—IX
作者:R. Bloch、P. Le Perchec、F. Rouessac、J.-M. Conia
DOI:10.1016/s0040-4020(01)90982-2
日期:1968.1
28 and 29, and 35, but in this case, the reaction appeared more difficult. The thermocyclization process of ethylenic carbonyl compounds and related systems (A), and the thermal cleavage of cyclic analogs (B) are discussed, all these rearrangements involving an intramolecular hydrogentransfer.
The Thermal Isomerizations of Bicyclo[2.1.0]pent-5-yl Methyl Ketones:endo-exo stereomutation and cyclopropyl-allylic rearrangement to cyclopent-2-enyl methyl ketones
Bicyclo[2.1.0]pent-5-yl methyl ketones undergo two thermalisomerization reactions. The endo-exo stereomutation follows the ring-flip path in better than 90%, with inversion of the configuration of the angular carbon atoms by cleavage and reclosure of the central bond. Stereomutation and cyclopropyl-allylic rearrangement to cyclopent-2-enyl methyl ketone do not involve a common intermediate and proceed