Untersuchungen zur Kn�pfung der Peptidbindung mit ?-trifluormethylsubstituierten ?-Aminos�uren
作者:Wolfgang Hollweck、Klaus Burger
DOI:10.1002/prac.19953370183
日期:——
The reaction of ol-trifluoromethyl substituted N-(t)butoxycarbonyl amino acids (Boc-TFM-Xaa-OH) 1 with dicyclohexylcarbodiimide results in formation of 2-(t)butoxy-4-trifluoramethyl-5(4H)-oxazolones 2 within minutes. Compounds 2 react with amino acid esters to give Boc protected dipeptide esters 4. However, at room temperature compounds 2 decompose to give Leuchs anhydrides 3, via retro-ene reaction. Therefore, alpha-trifluoromethyl substituted N-(t)butoxycarbonyl amino acids (Boc-TFM-Xaa-OH) are of limited value for peptide synthesis.
Designing a Planar Chiral Rhodium Indenyl Catalyst for Regio- and Enantioselective Allylic C–H Amidation
作者:Caitlin M. B. Farr、Amaan M. Kazerouni、Bohyun Park、Christopher D. Poff、Joonghee Won、Kimberly R. Sharp、Mu-Hyun Baik、Simon B. Blakey
DOI:10.1021/jacs.0c07305
日期:2020.8.12
Chiral variants of group IX Cp and Cp* catalysts are well established and catalyze a broad range of reactions with high levels of enantioselectivity. Enantiocontrol in these systems results from ligand design that focuses on appropriate steric blocking. Herein we report the development of a new planar chiral indenyl rhodium complex for enantioselectiveC-H functionalization catalysis. The ligand design