- STEREOSPECIFIC SYN-ACYLAMIDATION OF OLEFINS
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Acylamidation of 1-methylcyclopentene by acetyl boronfluoride - acetonitrile complex proceeds stereospecifically with syn-addition.
- Gridnev, I. D.,Buevich, A. V.,Sergeyev, N. M.,Balenkova, E. S.
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- General Methodology for the Topologically Selective Preparation of Linear and Nonlinear Tricyclopentanoids of Hirsutane and Isocomene Type via a Claisen Rearrangement/Cyclopentene Annulation Sequence. Total Synthesis of (+/-)-Epiisocomene
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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 thesynthesis 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.
- Hudlicky, Tomas,Kwart, Lawrence D.,Tiedje, Mark H.,Ranu, Brindaban C.,Short, Robert P.,et al.
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p. 716 - 727
(2007/10/02)
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- SCOPE AND STEREOCHEMICAL COURSE OF THE (TRIMETHYLSILYL)CYCLOPENTENE ANNULATION
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A new, regiospecific annulation approach to highly substituted 5-membered carbocycles has been developed.The "TMS-cyclopentene annulation" involves the reaction of (trimethylsilyl)allenes with electrondeficient alkenes and alkynes in the presence of titanium tetrachloride to afford, in a single step, a functionalized and highly substituted TMS-cyclopentene derivative.Annulations employing α, β-unsaturated ketones proceed stereoselectively via suprafacial addition to the enone.Some useful transformations of the annulation products are also described; for example, treatment with K2CO3-methanol or HF in acetonitrile effects isomerization and desilylation yielding α, β-unsaturated ketones.
- Danheiser, Rick, L.,Carini, David, J.,Fink, David M.,Basak, Ajoy
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p. 935 - 948
(2007/10/02)
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- ALUMINUM OXIDE CATALYZED ISOMERIZATION OF ACYLATED CYCLOALKENES
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A 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.
- Hudlicky, T.,Srnak, T.
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p. 3351 - 3354
(2007/10/02)
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