Synthesis of threo-β-aminoalcohols from aminoaldehydes via chelation-controlled additions. Total synthesis of l-threo sphingosine and safingol
作者:Michael E. Jung、Sung Wook Yi
DOI:10.1016/j.tetlet.2012.05.153
日期:2012.8
threo-β-amino alcohol derivatives through chelation with the carbamoyl moiety. The carbamate group is a stronger chelating group than other potentially good chelators, for example ethers, esters, thioethers, and gives good diastereoselectivity with cuprates. Thus addition of lithium divinylcuprate to the aldehyde generated from the serine derivative 25 in the presence of extra copper for chelation
Electrophilic fluorination of stereodefined disubstituted silyl ketene hemiaminals <i>en route</i> to tertiary α-fluorinated carbonyl derivatives
作者:Jian Qiang Huang、Zackaria Nairoukh、Ilan Marek
DOI:10.1039/c8ob00067k
日期:——
A highly diastereoselective synthesis of tertiary α-fluoro carbonyl compounds is reported in only two chemical steps from a simple alkyne through the reaction of stereodefined fully substituted silyl ketene hemiaminal derivatives with Selectfluor.
Coupling reactions of epoxide linked to a secondary oxygen group with Gilman reagents were examined. The regiochemical direction depended on whether there is TMS or MOM as a protective group of the secondary alcohol. anti-Epoxy alcohol 6 tended to react with Me2CuLi at the C4 position to generate 1,2-diol 22 as a major component. Epoxide 7 linked to a trimethylsilyloxy group displayed selective formation
Stereoselective synthesis of α-hydroxy-β-amino acid derivatives from β-hydroxy-γ,δ-unsaturated sulfilimine
作者:Sadagopan Raghavan、Shaik Mustafa
DOI:10.1016/j.tetlet.2008.03.114
日期:2008.5
The first report on the use of N-sulfinyl benzylcarbamate for the preparation of N-Cbz sulfiliminefrom the corresponding sulfoxide is reported. The sulfilimine moiety is utilized as an intramolecular nucleophile for the regio- and stereoselective heterofunctionalization of an alkene to furnish a bromo carbamate which is used as a key advanced intermediate in the synthesis of representative α-hydroxy-β-amino