کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5280481 | 1385648 | 2005 | 6 صفحه PDF | دانلود رایگان |
4-Phenylsulfanyl-2-(2-phenylsulfanylethyl)but-1-ene (2) has proved to be an appropriate and new 3-methylidenepentane-1,5-dianion synthon. The reaction of 2 with an excess of lithium powder and a catalytic amount of DTBB (2.5%) in the presence of a carbonyl compound in THF at 0 °C, leads, after hydrolysis, to the expected methylidenic diols 3. These diols when subjected to successive hydroboration-oxidation and final oxidation, undergo spontaneous cyclisation to furnish a series of cis-perhydropyrano[2,3-b]pyrans (4) in a highly diastereoselective manner (>99% de). Additionally, diols 3 also undergo double intramolecular iodoetherification promoted by a silver salt, to furnish the corresponding 1,7-dioxaspiro[4.5]decanes (6) in very high yields.
Journal: Tetrahedron Letters - Volume 46, Issue 38, 19 September 2005, Pages 6519-6524