WebMar 15, 2004 · The palladium-catalyzed cycloreduction of 5-allen-1-ynes gave the corresponding 1,2-bisalkylidenecyclopentanes in excellent chemoselectivity and chemical yields. Incorporating an electron-withdrawing group at the acetylenic position showed to … WebCycloreduction of the enyne 2 to a precursor of the title compound 1 is the key step in a total synthesis of 1. The reaction occurs under Pd catalysis with a yield of 86%. This is a case in which the Alder ene reaction proved unsuccessful. Compound 1 is the aglycone of the clinically interesting antitumor agent phyllanthoside (TIPS = i Pr 3 Si).
Borane-mediated aldol cycloreduction of monoenone …
WebFeb 27, 2007 · We have discovered a new method employing Pd-catalyzed cycloreduction of conjugated enynals 1 bearing an alkyne unit leading to the corresponding 2- (2-methylenecycloalkyl)-furans 2a − j and a related compound 7 in good to excellent yields. … WebMay 5, 2003 · In conclusion, we have accomplished a cascade Pd-catalyzed cycloreduction method of haloene-ynes. This method could be an alternative of diyne cycloreduction and enyne cyclization. Conjugated dienes or styrene derivatives obtained by this method could serve as a valuable synthetic building block. Acknowledgements incites metrics
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WebFeb 23, 2024 · An up to 99:1 stereochemical excess of 3 is reported for the cycloreduction of the title enynes 1 using a palladium-based catalyst and formic acid. The two-step process involves β-elimination of the coordinated enyne to form diene 2, followed by 2 recoordinating and the regio- and stereoselective reduction to produce the γ,δ-unsaturated carbonyl … WebAug 14, 2002 · Cycloreduction of monoenone monoaldehyde 1a in the presence of d (3)-phenylsilane reveals incorporation of a single deuterium at the enone beta-position as an equimolar mixture of epimers, inferring rapid isomerization of the … WebMar 15, 2004 · This cycloreduction of 4a in 1,4-dioxane occurred even at room temperature very slowly (entry 1) and completed at 60 °C in 1 h to give the cycloreduced product 5a without formation of other byproducts (entry 2). The optimal conditions (entry 3) were applied to 4b and 4c, which have a methyl substituent on either 1 or 3-allenic … incites journal of citation reports