Asymmetric synthesis of L-azetidine-2-carboxylic acid and 3-substituted congeners—conformationally constrained analogs of phenylalanine, naphthylalanine, and leucine
Enantiopure L-azetidine-2-carboxylic acid, the (3R)-phenyl, (3R)-naphthyl and (3S)-isopropyl analogs were prepared based on a zinc-mediated asymmetric addition of allylic halides to the camphor sultam derivative of glyoxylic acid O-benzyl oxime.
Palladium−Indium Iodide-Mediated Allylation and Propargylation of Glyoxylic Oxime Ether and Hydrazone: The Role of Water in Directing the Diastereoselective Allylation
Allylation and propargylation of glyoxylic oximeether in the presence of a catalytic amount of palladium(0) complex and indium(I) iodide were studied. Excellent diastereoselectivities in allylation were achieved in the presence of water, although low diastereoselectivities were observed in the absence of water. Propargylation of glyoxylic oximeether proceeded with good diastereoselectivities in the
Excellent diastereoselective allylation of camphor derived glyoxylic oxime ethers mediated by a Lewis acid
作者:Neelesh A. Kulkarni、Kwunmin Chen
DOI:10.1016/j.tetlet.2005.10.171
日期:2006.1
The nucleophilic allylation of camphor derived glyoxylic oxime ethers was carried out using allyltributyltin in the presence of Sn(OTf)2 affording the corresponding homoallylic amines in high chemical yields (up to 94%) and excellent stereoselectivities (up to >99%).
Two relatively weak herbicides, hydantocidin phosphate and hadacidin were linked by a C(3) chain to afford a potent inhibitor (the 2S hybrid is shown) of the enzyme adenylosuccinate synthetase. The crystal structures of the bisubstrate-enzyme complexes were determined.