Showing papers on "Total synthesis published in 1988"
TL;DR: In this article, a convergent asymmetric synthesis of the polyether antibiotic X-206 has been achieved through the synthesis and coupling of the CI-C16 and C17-C37 synthons 16 and 17, respectively.
Abstract: A convergent asymmetric synthesis of the polyether antibiotic X-206 has been achieved through the synthesis and coupling of the CI-C16 and C17-C37 synthons 16 and 17, respectively. All absolute stereochemical relationships within the molecule were controlled by application of recent methodological advances in asymmetric synthesis. In the synthesis of subunit 16, both the alkylation and aldol reactions of chiral imide-derived enolates were utilized to establish the five stereogenic centers at C2-C4 and C9-CIo, while the stereochemistry at C14 was indirectly controlled by the Sharpless asymmetric epoxidation. The C7 and Cl l stereocenters, which are situated at the two assemblage pints for 16, were established through internal asymmetric induction. The synthesis of the more complex c17<37 subunit 17 followed a similar strategy for absolute stereocontrol. Chiral enolate methodology was employed to define the stereogenic centers at C18, C,,, and C23 while asymmetric epoxidation was used to create the oxygen-bearing centers at C30-C31 and Cj4-C3). The remaining three stereogenic centers at Cz0, C,,, and C28 were controlled by internal asymmetric induction. The successful construction of this synthon relied upon the development of an efficient assemblage reaction in which three fragments comprising the entire carbon framework of 17 were united in
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TL;DR: Synthese des triquinones oxygenes du titre a partir de la methyl-6a tetrahydro-3,3a,6a cyclopenta [b] furannone-2
Abstract: Synthese des triquinones oxygenes du titre a partir de la methyl-6a tetrahydro-3,3a,6a cyclopenta [b] furannone-2
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130 citations
TL;DR: Preparation a partir d'un trimethyl-2,4,4 vinyl-3 cyclohexene-2ol (issu de l'α-ionene) and l'acide tosyl-3 propiolique.
Abstract: Preparation a partir d'un trimethyl-2,4,4 vinyl-3 cyclohexene-2ol (issu de l'α-ionene) et de l'acide tosyl-3 propiolique
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TL;DR: Synthese a partir du dimethyl-4,4 perhydropyrannyloxy pentanal via une dihydro-1,2 furannone-2 substituee.
Abstract: Synthese a partir du dimethyl-4,4 perhydropyrannyloxy pentanal via une dihydro-1,2 furannone-2 substituee
TL;DR: Venustatriol (1 ) has been synthesized by an enantioselective and convergent route via key intermediates 9 and 15 as discussed by the authors, and it has been shown that it can be synthesized using a key intermediate.
TL;DR: An enantioselective route for the total synthesis of ginkgolide B, a potent antagonist of platelet activating factor, has been developed which is based on enanti-lective reduction of enone 3 to the (R )-alcohol 5 and subsequent diastere-selective anti-S N 2' displacement to form 7. Intermediate 7 was converted in several steps to tetracyclic lactone 2 which was obtained in optically pure form simply by recrystallization.
TL;DR: In this paper, a synthesis of the parent carbocyclic subunit of NCS Chrom A (1) is described, which provides corroborative support for the assigned but unprecedented structure of the active subunit.
TL;DR: Synthese de spiroacetals des systemes dioxa-1,7spiro [5.5] undecane et Dioxa]-1,6spiro as mentioned in this paper [4] decane a partir d'α-hydroxyalkyl-5 furannebutanols-2 et -furannepropanols -2 via la cyclisation acide des alkyl-2 dihydro-3,6 hydroxy-6 w-hydroxyl- et -propyl-2 pyrannones
Abstract: Synthese de spiroacetals des systemes dioxa-1,7spiro [5.5] undecane et dioxa-1,6spiro [4.5] decane a partir d'α-hydroxyalkyl-5 furannebutanols-2 et -furannepropanols-2 via la cyclisation acide des alkyl-2 dihydro-3,6 hydroxy-6 w-hydroxybutyl- et -propyl-2 pyrannones-3
TL;DR: In this paper, an approach to elemanolides with additional oxygen functionalities is proposed by modification of the basic concept, which is used for the oxidative generation of terpenoid exo-methylene lactone and furan units.
TL;DR: In this article, a general procedure for cyclopentane synthesis based on free-radical cyclization of thioacetals is described, which permits the rapid assembly of various ring systems bearing useful functionality for use in total synthesis.
TL;DR: An enantioselective total synthesis of bilobalide 1 has been effected from diester 5 using stereospecific conversion to 7 via intermediate 6 as discussed by the authors, which has been shown to work well in a number of applications.
TL;DR: An enantioselective route for the total synthesis of forskolin, a potent activator of adenylate cyclase, has been developed which is based on reduction of dienone 3 to the (S)-alcohol 4 and conversion in two steps to tricyclic lactone 9, obtained in optically pure form simply by recrystallization as mentioned in this paper.
TL;DR: In this article, the synthese a partir du (+) carene du t-butyldimethylsiloxy-4' butene-2'yl-6 hydroxycarbonyl-4 oxo-5 trimethyl-3,8,8 bicyclo [5.1.0] octanepropionate-4 de methyle est effectuee.
Abstract: La synthese a partir du (+) carene du t-butyldimethylsiloxy-4' butene-2'yl-6 hydroxycarbonyl-4 oxo-5 trimethyl-3,8,8 bicyclo [5.1.0] octanepropionate-4 de methyle est effectuee. On prepare ensuite dans le but de determiner la stereochimie un derive de methano cyclopropa cyclodeca furanne