Showing papers on "Annulation published in 1979"
39 citations
31 citations
20 citations
TL;DR: In this article, the development of a new cyclopentenone annulation sequence of general scope which involves Friedel-Crafts acylation of a vinylsilane with an α,β-unsaturated acid chloride followed by Nazarov cyclization is reported.
20 citations
TL;DR: The bicyclic αβ-unsaturated ketone (2) was converted into tricyclic ketone by as mentioned in this paper via an 11-step sequence, thus completing a new total synthesis of (±)-zizaene.
Abstract: The bicyclic αβ-unsaturated ketone (2), conveniently prepared by thermal rearrangement of (1), is converted, via an 11-step sequence, into the tricyclic ketone (15), thus formally completing a new total synthesis of (±)-zizaene (3).
18 citations
TL;DR: Vinyltrimethylsilane reacts with cyclic α,β -unsaturated acid chlorides in the presence of stannic tetrachloride to give bicyclo[n.3.0]enones as mentioned in this paper.
14 citations
TL;DR: In this article, a total synthesis of (±)-β-himachalene, involving the Cope rearrangement of the substituted β-(2-vinylcyclopropyl) enone as a key step, is described.
Abstract: A total synthesis of (±)-β-himachalene (1), involving the Cope rearrangement of the substituted β-(2-vinylcyclopropyl) enone (9) as a key step, is described.
12 citations
TL;DR: In this article, the title sesquiterpene is synthesized by means of the new cyclopentenone annulation which involves acid-treatment of IIIb, and the ester group of the resulting V is transformed selectively into isopropenyl appendage of the trans configuration to the two methyl groups.
9 citations
TL;DR: In this paper, the synthesis of dl-elaeokanine-A and Dl-ELAEKANINE-C was described by an approach which utilizes a nitrone cyclo-addition to generate a β-aminoketone, which upon annulation produces one or the other of the title alkaloids depending upon conditions.
9 citations
TL;DR: In this article, a new method of annelation utilizing the reaction of vicinal diester dianions with allylic and benzylic α,ω-dihalidesis was described.
7 citations
TL;DR: Asymmetric synthesis of D-homoestrone methyl ether was achieved by a new annalation reaction by using a new method to combine H2O and Na6(CO3SO4) with Na2SO4 to form Na2CO3.
TL;DR: In this paper, the annulation of the rings of an 18-alkoxybicyclo[4.3.0]-3-nonene-7-carboxylates was found to depend on the extraction of alcohol and benzene.
Abstract: Fragmentation of ethyl(18-alkoxybicyclo[4.3.0]-3-nonene-7-carboxylates) was found to depend on the annulation of the rings. Following ionization, the cis-annulated isomers lose alcohol and benzene, while the trans-isomers fragment by other reaction paths. The regiospecificity of alcohol elimination from both the ester and the ether groups was determined by using deuterium-labelled analogues. A mechanism is discussed which rationalizes the differences observed in the spectra of the annulation isomers.
TL;DR: In this paper, the major annulation product from 4-vinylfuran-2(5H)-one and 2-methoxycarbonyl-6-methylcyclohexanone, was transformed into racemic frullanolide.
Abstract: 2,4,5,5a,6,7,8,9a,9bα-Decahydro-9aβ-hydroxy-5aβ-methoxycarbonyl-9β-methyl-2-oxo-naphtho[1,2-b]furan, the major annulation product from 4-vinylfuran-2(5H)-one and 2-methoxycarbonyl-6-methylcyclohexanone, was transformed into racemic frullanolide
TL;DR: A simple synthesis of δ-oxoalkyl (phenyl) phosphine oxides has been described in this paper, which can be used to obtain I-phenyl-2-hydroxyphospholane 1-oxides being precursors of phosphafuranoses.
Abstract: A simple synthesis of δ-oxoalkyl (phenyl) phosphine oxides has been described. δ-Oxoalkyl (phenyl) phosphine oxides have been found to cyclize in the presence of acid to afford I-phenyl-2-hydroxyphospholane 1-oxides being precursors of phosphafuranoses.