Metal-graphite reagents in carbohydrate chemistry, IX fragmentations of 1-deoxy-1-iodo-2,3;4,5-di-O-isopropylidene pentitols
作者:Alois Fürstner
DOI:10.1016/s0040-4039(00)97457-4
日期:——
Compounds and , each readily available in both enantiomeric forms smoothly fragment on treatment with zinc/silver-graphite or potassium-graphite laminate (C8K), respectively, thus affording the full set of stereoisomeric 1,2-O- isopropylidene-pent-4-enitols.
and/or bicyclic oxaheterocyclic derivatives depending on a starting alkenol. The substrate scope and proposed mechanism of Pd-catalysed cyclisation reactions are also discussed. Moreover, the diastereoselective Pd-catalysed cyclisation of appropriate alkenols to tetrahydrofurans and subsequent cyclisation provided properly substituted 2,5-dioxabicyclo[2.2.1]heptane and 2,6-dioxabicyclo[3.2.1]octane
Ultrasound-accelerated synthesis of chiral allylic alcohols promoted by indium metal
作者:J.S Yadav、B.V.S Reddy、K Srinivasa Reddy
DOI:10.1016/s0040-4020(03)00736-1
日期:2003.7
The 2-iodomethyl-O-isopropylidine acetals undergo smoothly β-elimination by indium metal in methanol under sonication to afford the corresponding allylic alcohols in excellent yields with high selectivity. This method tolerates both acid and base labile functional and protecting groups and also free hydroxyl groups present in the molecule. Improved yields and enhanced rates are the remarkable features