New Amino-protective Reagents for<i>t</i>-Butoxycarbonylation and Benzyloxycarbonylation of Amines and Amino Acids
作者:Sunggak Kim、Jae In Lee、Kyu Yang Yi
DOI:10.1246/bcsj.58.3570
日期:1985.12
New amino-protective reagents for t-butoxycarbonylation and benzyloxycarbonylation of amines and aminoacids have been developed. t-Butyl 2-pyridyl carbonate and t-butyl S-(2-pyridyl) thiocarbonate react cleanly with various amines and aminoacids to afford N-Boc amines and N-Boc aminoacids in high yields. Benzyl 2-pyridyl carbonate and O-benzyl S-(2-pyridyl) thiocarbonate are also found to be very
Chelation-Based Homologation by Reaction of Organometallic Reagents with O-Alkyl S-Pyridin-2-yl Thiocarbonates: Synthesis of Esters from Grignard Reagents
The one-carbon homologative esterification of Grignardreagents with O-alkyl S-pyridin-2-yl thiocarbonates has been explored. This one-step synthesis of esters from Grignardreagents is the first case to involve chelation-stabilized intermediates.
δ,ϵ-Unsaturated oximes, on heating with O-alkyl S-(pyridin-2-yl)carbonothioates (PySCO2R) in refluxing toluene, undergo intramolecular cycloaddition to give N-alkoxycarbonylated multi-cyclic compounds. Mechanistic studies indicate that the reaction involves direct generation of N-alkoxycarbonyl nitrones followed by cycloaddition, instead of intramolecular oxime-olefin cycloaddition (IOOC) followed