An Amino Alcohol Ligand for Highly Enantioselective Addition of Organozinc Reagents to Aldehydes: Serendipity Rules
作者:William A. Nugent
DOI:10.1021/ol0259488
日期:2002.6.1
bis(2-bromoethyl) ether. Subsequent hydrogenation over 5% Rh on alumina in the presence of morpholine unexpectedly stops at the hexahydro derivative 4. Amino alcohol 4 promotes the enantioselectiveaddition of diethylzinc to aldehydes at room temperature in up to 99% enantiomeric excess.
A Tandem Ester Cleavage-Michael Addition Reaction for the Synthesis of Oxygen Heterocycles
作者:R. A. Bunce、M. J. Bennett
DOI:10.1080/00397919308013298
日期:1993.4
Abstract A tandem ester cleavage-Michael addition sequence has been developed for the preparation of five- and six-ring oxygen heterocycles bearing an acetic acid residue at C-2. Treatment of ethyl 6- or 7-acetyloxy-2-alkenoates with ethanolic sodium ethoxide affords the tetrahydrofuran and tetrahydropyran products in 70–90% yields. The reaction is clean and appears to be a generalroute for the preparation