Copper Phosphoramidite-Catalyzed Enantioselective Desymmetrization of <i>meso</i>-Cyclic Allylic Bisdiethyl Phosphates
作者:Umberto Piarulli、Christelle Claverie、Philippe Daubos、Cesare Gennari、Adriaan J. Minnaard、Ben L. Feringa
DOI:10.1021/ol035807l
日期:2003.11.1
A highly regio-, diastereo-, and enantioselective desymmetrization of five-, six-, and seven-membered meso-cyclic allylic bis-diethyl phosphates (2a, 2b, and 2c, respectively) was obtained with diethylzinc, using catalytic amounts of [Cu(OTf)](2).C6H6 and phosphoramidite ligands 5. Enantiomeric excesses of up to 87, 94, and >98% were obtained for the addition of diethylzinc to cyclopentene, cyclohexene, and cycloheptene bis-diethyl phosphates, respectively.
A highly regio-, diastereo- and enantioselective desymmetrization of five-, six-, and seven-membered meso, cyclic allylic bis(diethyl phosphates) (3–5) with organozinc reagents was developed, usingcatalytic amounts (10 mol%) of [Cu(OTf)]2·C6H6 and two different classes of chiral ligands: Schiff bases 1 and phosphoramidites 2. Good to excellent enantioselectivities were obtained for every substrate