Radical cyclization of vinylic ethers: expedient synthesis of (+)-monocerin.
TL;DR: Stereoselective synthesis of (+)-monocerin was accomplished via radical cyclization of a vinylic ether intermediate.
About: This article is published in Organic Letters.The article was published on 2008-06-13. It has received 22 citations till now. The article focuses on the topics: Radical cyclization & Monocerin.
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TL;DR: Stereoselective oxylactonization of ortho-alkenylbenzoate with chiral hypervalent iodine is applied to the asymmetric synthesis of 4-oxyisochroman-1-one polyketide metabolites including 4-hydroxymellein.
79 citations
TL;DR: The stereoselective gold-catalyzed 6-endo cyclization of various β-hydroxyallenes in the presence of N-iodosuccinimide affords iodinated dihydropyrans in good yield and opens an access to α-Hydroxy allenes that are converted in a second gold-Catalyzed cyclization into furopyrans which occur in various natural products.
51 citations
TL;DR: A review of the reactions and synthesis of furans, benzofurans, and their derivatives can be found in this article, where a 2-substituted furan was shown to undergo spirocyclization at the 2-position, irrespective of the length of the carbon linker.
Abstract: Publisher Summary This chapter reviews papers that were published in 2006 on the reactions and syntheses of furans, benzofurans, and their derivatives. Like 2005, many new naturally occurring molecules containing tetrahydrofuran and dihydrofuran rings were identified in 2006. Several examples reported in 2006 demonstrate that 2-substituted furans underwent spirocyclization at the 2-position. The reaction of a furan tethered at the 2-position to an iminium ion gave a spiro-2,5-dihydrofuran derivative as the sole diastereoisomer. This spirocyclization that proceeded irrespective of the length of the carbon linker was employed to construct the ABC tricyclic core of manzamine A. Spirocyclization was also the reaction pathway under radical conditions if furan was tethered to a radical precursor at the 2-position. When furans were tethered to silyl enol ethers at the 2-position, spiroannulation also occurred at the 2-position under electrochemical conditions. Furan that was loaded on a soluble dendritic polyglycerol support could be efficiently oxidized electrochemically to a 2,5-dihydro-2,5-dimethoxyfuran, which served as an intermediate in the synthesis of a pyrrole library.
39 citations
TL;DR: The cis-fused furobenzopyranones of 7-O-demethylmonocerin and (+)-monOCerin were efficiently constructed via an intramolecular nucleophilic trapping of a quinonemethide intermediate, which was obtained by benzylic oxidation of fusarentin 6-methyl ether using hypervalent iodine reagent.
Abstract: A concise asymmetric total synthesis of a fiisarentin ether (1) with sequential biomimetic transformation to its analogues fusarentin 6,7-dimethyl ether (2), 7-O-demethylmonocerin (3), and (+)-monocerin (4) has been accomplished. The cis-fused furobenzopyranones of 7-O-demethylmonocerin (3) and (+)-monocerin (4) were efficiently constructed via an intramolecular nucleophilic trapping of a quinonemethide intermediate, which was obtained by benzylic oxidation of fusarentin 6-methyl ether (1) using hypeivalent iodine reagent.
31 citations
TL;DR: In this paper, the first total synthesis of (12R)- and (12S)-12-hydroxymonocerins is described and the oxolane-fused isochroman-1-one framework is stereoselectively constructed via a double oxy-cyclization using a lactate-based chiral hypervalent iodine reagent.
Abstract: The first total syntheses of (12R)- and (12S)-12-hydroxymonocerins are described. The oxolane-fused isochroman-1-one framework is stereoselectively constructed via a double oxy-cyclization using a lactate-based chiral hypervalent iodine reagent. A catalytic variant of the double oxy-cyclization is also demonstrated using a chiral iodoarene as the precatalyst and m-CPBA as the co-oxidant.
29 citations
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TL;DR: A highly stereoselective synthesis of the C(1)-C(11) fragment 4 of peloruside A has been accomplished via a stereoselectedive double allylboration and an intramolecular epoxide opening to provide the functionally dense C(3)-C (11) segment 14.
52 citations
TL;DR: Both the naturally occurring enantiomer and the racemate of monocerin [1a, (2 S,3a R,9b R )-2,3,3a,9b-tetrahydro-6-hydroxy-7,8-dimethoxy-2-propyl-5 H -furo[3,2-c ][2]benzopyran-5-one] were synthesized for the first time.
49 citations
TL;DR: In this article, an antifungal metabolite of Helminthosporium monoceras is shown to be 2,3,3a,9b-tetrahydro-6-hydroxy-7,8-dimethoxy-2-n-propyl-5H-furo[3,2-c][2]benzopyran-5-one (Ia).
Abstract: Monocerin, an antifungal metabolite of Helminthosporium monoceras, is shown to be 2,3,3a,9b-tetrahydro-6-hydroxy-7,8-dimethoxy-2-n-propyl-5H-furo[3,2-c][2]benzopyran-5-one (Ia). Structures are also assigned to three related metabolites—hydroxymonocerin (Id), monocerone (Ie), and monocerolide (V).
42 citations