Metal-Catalyzed Cyclization of β- and γ-Allenols Derived from D-Glyceraldehyde-Synthesis of Enantiopure Dihydropyrans and Tetrahydrooxepines: An Experimental and Theoretical Study
作者:Benito Alcaide、Pedro Almendros、Teresa Martínez del Campo、Elena Soriano、José L. Marco-Contelles
DOI:10.1002/chem.200901180
日期:2009.9.14
Regiocontrolled metal‐catalyzed preparations of enantiopuredihydropyrans and tetrahydrooxepines have been synthesized starting from β‐ and γ‐allenols derivedfrom D‐glyceraldehyde. The PdII‐catalyzed cyclizative coupling reactions of β‐allenols 1 a and 1 b with allyl bromide effectively afforded enantiopure tetrafunctionalized dihydropyrans through a 6‐endo oxycyclization protocol, whereas the gold‐
Chemo- and Regioselective Palladium-Catalyzed Oxycyclization Reactions of Allendiols: Preparation of Five-, Six-, and Eight-Membered Cycles
作者:Benito Alcaide、Pedro Almendros、Rocío Carrascosa、Teresa Martínez del Campo
DOI:10.1002/chem.200802675
日期:2009.3.2
Positive discrimination: Chemo‐ and regioselective palladium‐catalyzed cycloetherification of allendiols, namely β,γ‐ and γ,δ‐allendiols, may occur by judicious choice of palladium‐catalyzed conditions owing to their potential ability to discriminate between both nucleophilic sites (see scheme).
Metal-Catalyzed Cycloetherification Reactions of β,γ- and γ,δ-Allendiols: Chemo-, Regio-, and Stereocontrol in the Synthesis of Oxacycles
作者:Benito Alcaide、Pedro Almendros、Rocío Carrascosa、Teresa Martínez del Campo
DOI:10.1002/chem.201001520
日期:2010.11.22
and stereocontrolled metal‐catalyzed oxycyclization reactions of β,γ‐ and γ,δ‐allendiols, which were readily prepared from (R)‐2,3‐O‐isopropylideneglyceraldehyde. The application of PdII, PtII, AuIII, or LaIII salts as the catalysts gives controlled access to differently sized oxacycles in enantiopure form. Usually, chemoselective cyclization reactions occurred exclusively by attack of the secondary hydroxy