A General Method for the Enantioselective Synthesis of Pantolactone Derivatives
作者:David A. Evans、Jimmy Wu、Craig E. Masse、David W. C. MacMillan
DOI:10.1021/ol026489d
日期:2002.10.1
An efficient enantioselective synthesis of beta,beta-dialkyl-gamma-substituted pantolactones has been achieved utilizing the cationic [Sc((S,S)-R-pybox)](Cl)(2)(+), R = Ph (9), t-Bu (10), complex in a catalyzed aldol reaction as the key step. The pantolactone derivatives are isolated in high enantiomeric excesses. [reaction: see text]
<i>C</i><i><sub>2</sub></i><i>-</i>Symmetric Sc(III)-Complexes as Chiral Lewis Acids. Catalytic Enantioselective Aldol Additions to Glyoxylate Esters
作者:David A. Evans、Craig E. Masse、Jimmy Wu
DOI:10.1021/ol026488l
日期:2002.10.1
Cationic Lewisacidcomplexes [Sc(pyridyl-bis(oxazolinyl)](Cl(2))SbF(6) 1a and 1b catalyze aldol reactions with ethyl glyoxylate with enantioselectivities ranging from 90 to 99% ee and syn reaction diastereoselections ranging from 90:10 to 95:5. [reaction: see text]