0000000000484878
AUTHOR
Martin Brunner
showing 2 related works from this author
Diastereoselective formation of highly functionalised α-substituted amino acid derivatives via aldol addition
2005
Abstract Highly diastereoselective aldol additions of (2 R ,4 S )-3- tert -butyl 4-methyl 2- tert -butyloxazolidine-3,4-dicarboxylate ( 1 ) are reported. The utility of the highly substituted oxazolidines of type 1 for diastereoselective α-addition of the fully protected amino acid l -serine with achiral and chiral carbonyl compounds is demonstrated and the relative and absolute configuration of the aldol products are discussed on the basis of NOESY data and solid state structures of selected examples. The aldol products represent highly useful intermediates in the syntheses of sphingosine-related metabolites.
Stereocontrolledα-Alkylation of Fully ProtectedL-Serine
2004
Diastereoselective alkylation of the (2S,4S) and (2R,4S) diastereomers of 3-tert-butyl 4-methyl 2-tert-butyl-1,3-oxazolidine-3,4-dicarboxylate (1a/b) is reported. Formation of both diastereomers of these oxazolidines was achieved by changing the order of protection steps, and their relative and absolute configurations were determined by NOESY spectroscopy. The use of the bulky ring substituent tBu together with Boc as the N-protecting group led to the exclusive formation of only one alkylated diastereomer. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)