Amino acid-derived hydroxamic acids as chiral ligands in the vanadium catalysed epoxidation
作者:Andrei V. Malkov、Zaïnaba Bourhani、Pavel Kočovský
DOI:10.1039/b505324b
日期:——
New sulfonamide-derived hydroxamicacids have been developed as chiralligands for the V-catalysed asymmetricepoxidation, showing high reactivity at subzero temperatures and moderate to good enantioselectivity. The strong accelerating effect exhibited by the ligands of this type can be attributed to the sulfonamide functionality. A range of cinnamyl type allylicalcohols were epoxidised with up to
Oxazoline derivatives tagged with tosylated amino acids as recyclable organocatalysts for enantioselective allylation of aldehydes
作者:Debashis Ghosh、Arghya Sadhukhan、Nabin Ch. Maity、Sayed H. R. Abdi、Noor-ul H. Khan、Rukhsana I. Kureshy、Hari C. Bajaj
DOI:10.1039/c3ra47424k
日期:——
of amino acid-based oxazoline compounds have been prepared and successfully applied to the enantioselective allylation reaction of aldehydes. The fine-tuning of the structure of the oxazolines led to (S,S)-4 as an efficient organocatalyst which gave homoallyl alcohols in good yield (up to 90%) and excellent ee (up to 99%) for a wide range of substrates including aromatic, hetero-aromatic and α,β-unsaturated
Branch-Selective Addition of Unactivated Olefins into Imines and Aldehydes
作者:Jeishla L. M. Matos、Suhelen Vásquez-Céspedes、Jieyu Gu、Takuya Oguma、Ryan A. Shenvi
DOI:10.1021/jacs.8b11699
日期:2018.12.12
Herein we report the reductive coupling of electronically unbiased olefins with imines and aldehydes. Iron catalysis allows addition of alkyl-substituted olefins into imines through the intermediacy of free radicals, whereas a combination of catalytic Co(Sal t-Bu, t-Bu) and chromium salts enables a branch-selective coupling of olefins and aldehydes through the formation of a putative alkyl chromium intermediate