Chiral Oxime Ethers in Asymmetric Synthesis. 3.1 Asymmetric Synthesis of (R)-N-Protected α-Amino Acids by the Addition of Organometallic Reagents to the ROPHy Oxime of Cinnamaldehyde
摘要:
A new asymmetric synthesis of a-amino acids is described in which the key step is the diastereoselective addition of organometallic reagents to (R)-O-(1-phenylbutyl)cinnamaldoxime 5 to give hydroxylamines 6. Subsequent reductive cleavage of the N-O bond in the hydroxylamine 6 followed by N-protection gave the carbamates 7, which upon oxidation with ruthenium(III) chloride/periodate gave the N-protected amino acids 8. The method was also adapted to the synthesis of a quaternary amino acid 15 from the ketoxime ether 9.
Chiral oxime ethers in asymmetric synthesis. Part 5.1 Asymmetric synthesis of 2-substituted 5- to 8-membered nitrogen heterocycles by oxime addition–ring-closing metathesis
作者:James C. A. Hunt、Pierre Laurent、Christopher J. Moody
DOI:10.1039/b207235c
日期:——
Addition of organometallic reagents to chiral oxime ethers 1 derived from an unsaturated aldehyde, or addition of an alkene containing organometallic to chiral aldoxime ethers 2 results in highly stereoselective formation of the hydroxylamines 6. N-Allylation gives the dienes 7 which undergo ring-closingmetathesis (RCM) reaction to give the 5-, 6-, and 7-membered nitrogen heterocycles 8. Likewise
Addition of Organolithiums to the (<i>R</i>)-<i>O</i>-(1-Phenylbutyl)hydroxylamine (ROPH<sub>y</sub>) Oxime of Cinnamaldehyde. Asymmetric Synthesis of α-Aminoacids
A new asymmetric synthesis of α-aminoacids is described in which the key step is the diastereoselective addition of organolithium reagents to (R)-O-(1-phenylbutyl) cinnamaldoxime.