Juan F. Gil, D. Ramón, M. Yus
May 28, 1993
Citations
0
Influential Citations
45
Citations
Journal
Tetrahedron
Abstract
Abstract The reaction of 2-(4-chlorobutyl)-1,3-dioxolanes (1a–c) or 2-(4-chlorobutyl)-2-ethyl-1,3-dithiane (1d) with an excess of lithium powder and a catalytic amount of naphthalene (8 mol %) in THF at -78°C leads to a solution of the corresponding masked lithium δ-enolates 2, which react with different electrophiles (water, deuterium oxide, carbonyl compounds, carboxylic acid derivatives, dibenzyl disulfide or benzylideneaniline) to yield the expected products 3–15. In the presence of a catalytic amount of CuBr.Me2S the intermediate 2a reacts with cyclohex-2-enone giving the compound 16a through a conjugate addition. The deprotection of compounds 10a, 12a, 16a and 4b–6b with 2 N HCl gives the expected functionalized carbonyl compounds 17a–19a and 20b–22b, respectively. Finally, using silicon reagents it is possible to prepare alcohols 20a–25a, dienic alcohols 26a–29a and cyanooxepanes 30a–33a from the in situ generated hydroxyaldehydes of the type 17a with triethylsilane, allyltrimethylsilane and trimethylsilyl cyanide, respectively.