Diastereoselective Prins-Type Reaction of Cycloalkenylcyclopropanol Silyl Ethers and α,β-Unsaturated Aldehyde Acetals
作者:Ivan L. Lysenko、Heong-Sub Oh、Jin Kun Cha
DOI:10.1021/jo071272o
日期:2007.10.1
Electrophilic addition of 1-(1-cyclohexenyl)-1-cyclopropanol trimethylsilylether to α,β-unsaturated aldehyde acetals under Lewisacidic conditions proceeds with good to excellent diastereoselectivity to afford spirocyclobutanones containing three contiguous stereocenters. A convenient entry to enantioselective syntheses is available by use of a nonracemic C2-symmetric acetal. Elaboration of the resulting
Asymmetric Addition Reactions with Optimized Selenium Electrophiles
作者:Thomas Wirth、Gianfranco Fragale
DOI:10.1002/chem.19970031123
日期:1997.11
AbstractThe synthesis of various nonracemic diselenides by different methods is described. These diselenides are precursors for optically active selenium electrophiles. Their facial selectivity upon addition to styrene was investigated with respect to the chiral moiety neighboring the selenium. Diselenides 1 i, 1 n, and 1 v yielded addition products 7 with diastereomeric excesses up to 95%. Some diselenides, intermediates, and products of the addition reaction were investigated by 77Se NMR spectroscopy.