F. Alonso, J. Meléndez, M. Yus
Sep 19, 2005
Citations
0
Influential Citations
13
Citations
Journal
Tetrahedron Letters
Abstract
Abstract 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.