attached to 2-(hydroxymethyl)pyridinooxazoline and bis[4-(hydroxymethyl)oxazoline] compounds. The new ligands obtained were assessed in palladium-catalyzedallylicalkylations. The first type of ligands exhibited enantioselectivity similar to that of a benzoyl ester derivative, whereas the latter type of ligands afforded products with higher selectivity than the analogous benzoyl ester. The activity of the
Bisdiamidophosphite with a bisoxazoline moiety in palladium-catalyzed enantioselective allylation
作者:K. N. Gavrilov、S. V. Zheglov、V. K. Gavrilov、I. D. Firsin、M. G. Maksimova
DOI:10.1007/s11172-019-2564-6
日期:2019.7
A bisdiamidophosphite ligand with stereogenic phosphorus atoms as a part of 1,3,2-diaza-phospholidine rings and a bisoxazoline backbone was synthesized and studied in the Pd-catalyzed asymmetric allylic substitution. The use of this ligand provided up to 93% ee in the alkylation of (E)-1,3-diphenylallyl acetate with dimethyl malonate and up to 77% ee in the amination with pyrrolidine at quantitative conversion of the starting substrate.
A New Copper<sup>II</sup>/Isopropylidene-2,2-bis(oxazoline) Catalyst and Its Stable Reactive Complex with Acryloyloxazolidinone in Enantioselective Reactions
ghost: The [TIPS‐box/Cu(OTf)2] complex (box = isopropylidene‐2,2‐bis(oxazoline)) is a catalyst of the Diels–Alder and the 1,3‐dipolar cycloaddition between acryloyl‐1,3‐oxazolidin‐2‐one with cyclopentadiene and diphenylnitrone with ee values of 75 and 85 %, respectively. The reacting complex (see figure) of the above reactions was, for the first time, isolated and its structure determined by X‐ray spectroscopy
The diastereo- and enantioselective cyclopropanation of furans was achieved in up to 91% ee using a new set of chiral bis(oxazoline) ligands that are able to use secondary binding sites to enhance selectivity. In contrast, with substrates such as styrene and N-Boc-pyrrole, with which no secondary interactions with the ligands can occur, only moderate selectivities (<50% ee) were achieved. (C) 2003 Elsevier Science Ltd. All rights reserved.