Cuts both ways: The title reaction consists of an addition/cyclization/dehydration sequence and affords the biologically important chiral 3,5‐diaryl‐5‐(trifluoromethyl)‐2‐isoxazolines 1 in excellent yields with high ee values. The flexibility of accessing either the S or R enantiomers of the products has been achieved by the appropriate choice of phase‐transfer catalyst (2).
This work describes the optimization process for the synthesis of β-trifluoromethylated ketonesfrom trifluoromethylated allylicalcohols. This transformation proceeds through a ruthenium catalyzed isomerization under mild conditions with high atom economy. The effect of the CF3 group was analyzed and it provides fundamental insights into the isomerization reaction.
Enantioselective Synthesis of Trifluoromethylated Tertiary Thioethers through Organocatalytic Sulfa-Michael Addition of Thiols to β-Trifluoromethyl β,β-Disubstituted Enones
作者:Fu-Xue Chen、Yao-Feng Wang、Shaoxiang Wu、Pran Karmaker、Muhammad Sohail、Qi Wang
DOI:10.1055/s-0034-1380138
日期:——
Abstract An organocatalyticasymmetric sulfa-Michael addition of thiols to β-trifluoromethyl β,β-disubstituted (E)-enones in the presence of 10 mol% of a cinchona alkaloid-derived thiourea catalyst provides direct and simple access to chiraltrifluoromethyl tertiary thioethers in high yields and up to 76% ee. An organocatalyticasymmetric sulfa-Michael addition of thiols to β-trifluoromethyl β,β-disubstituted
作者:Amparo Sanz-Marco、Gonzalo Blay、Carlos Vila、José R. Pedro
DOI:10.1021/acs.orglett.6b01494
日期:2016.8.5
The enantioselective conjugate alkynylation of β-aryl-β-trifluoromethyl enones has been carried out using terminal alkynes and diethylzinc in the presence of 3,3′-bis(perfluorophenyl)BINOL as the chiral ligand to give the corresponding ketones bearing a trifluoromethylated propargylic quaternary stereocenter with fair to good enantioselectivities. Enones bearing a bulky 2-naphthyl attached to the carbonyl
Ether way: The cinchona‐alkaloid‐catalyzed title reaction was achieved in high yields with high to excellent ee values for the first time, and affords key intermediates for the biologically important 2 having a trifluoromethylated all‐carbon quaternary chiral center. Ether‐type catalysts (1) are more efficient in this transformation than the conventional hydroxy analogues.