Battsengel Gotov

Study of ligand and base effects on enantioselective allylation catalyzed by Pd(0) phosphine complexes in [bmim][PF6] ionic liquid

Enantioselective Pd-catalyzed allylic substitution of (rac)-(E)-1,3-diphenyl-3-acetoxyprop-1-ene with dimethyl malonate was studied in 3-butyl-1-methylimidazolium hexafluorophosphate ([bmim][PF6]) as an ionic liquid. The reactions were catalyzed by Pd(0) complexes of three homochiral ferrocenylphosphine ligands, (S,S)-iPr-Phosferrox, (S,R)-iPr-Phosferrox, (R,S)-BCyPFA and (R)-BINAP. Potassium carbonate and bis(trimethylsilyl)acetamide (BSA)/AcOK were tested as the bases and simple optimization of the reaction procedure was performed. Experiments with other soft nucleophiles also were carried out under optimized conditions.

Enantioselective allylic substitution catalyzed by Pd0–ferrocenylphosphine complexes in [bmim][PF6] ionic liquid

Enantioselective allylic substitution reactions of (rac)-(E)-1,3-diphenyl-3-acetoxyprop-1-ene with dimethyl malonate (DMM) are studied in 1-butyl-3-methylimidazolinium hexafluorophosphate ([bmim][PF6]) as an ionic solvent; the reactions are catalyzed by Pd0 complexes of two homochiral ferrocenylphosphine ligands, (S,R)-BPPFA and (R,S)-BPPFDEA with the recycling of the catalytic system being tested. A similar reaction with 1-phenyl-3-acetoxyprop-1-ene is also studied with only a linear achiral product being isolated.

Proline-catalysed asymmetric aldol reaction in the room temperature ionic liquid [bmim]PF6Electronic supplementary information (ESI) available: experimental details and 1H-NMR spectra of the prepared compounds. See http://www.rsc.org/suppdata/cc/b2/b206911c/

Proline-catalysed asymmetric direct aldol reaction of different aromatic aldehydes with acetone and several other ketones in the room temperature ionic liquid 1-n-butyl-3-methylimidazolium hexafluorophosphate achieved good yields of aldolisation products with reasonable enantioselectivities, even when just 1–5% of proline was used as the catalyst; immobilisation of the catalyst in an ionic liquid phase offers simple product isolation and reuse of the catalytical system in subsequent reactions.

Synthesis of silica-supported chiral ferrocenylphosphine ligands and their application in some stereoselective reactions

Synthesis of new BPPFA analogues, having exchanged one of the N-methyl groups for a long (–C10H20–) or short (–C4H8–) alkyl chain with a terminal methoxycarbonyl group, and their immobilization on silica are described. Immobilization resulted in considerable lowering of the reaction rates as well as stereoselectivity in hydrogenation reactions. On the other hand, both homogeneous 3a as well as immobilized ligand 6a with a longer spacer (–C10H20–) have activities and enantioselectivities in allylic nucleophilic substitution comparable to the known BPPFA ligand. This is true also for homogeneous ligand 3b with a shorter chain (–C4H8–), but its immobilization resulted in a big drop of activity as well as selectivity.

Novel Chiral 1-(ferrocenylalkyl)-(S)-prolinols and their Application in Enantioselective Synthesis

Abstract Diastereomeric ferrocenylphosphine ligands, (−)-( S , R , pS )-BPPF-Pro ( 3a ) and (+)-( S , S , pR )-BPPF-Pro ( 3b ), containing the ( S )-prolinol moiety were prepared. A detailed structural elucidation of these ligands was carried out using NMR. The Pd-complexes of these ligands were used for enantioselective catalysis of allylic substitution reactions of rac -( E )-1,3-diphenyl-3-acetoxyprop-1-ene with C-nucleophiles generated from pentan-2,4-dione and dimethyl malonate. A series of chiral ferrocene aminoalcohols with ( S )-prolinol moiety ( 4a – c ) were also prepared. The role of the configuration of stereogenic centers for stereoselectivity in diethylzinc addition to benzaldehyde was studied.

Microwave assisted acylation of methoxyarenes catalyzed by EPZG® catalyst

Solventless acylation and benzoylation of 1-methoxynaphthalene, 2-methoxynaphthalene and anisole with different acyl chlorides and anhydrides catalyzed with EPZG® under microwave irradiation were studied. The high yields of the monoacylation products were achieved in a very short time and diacetylation products were also isolated.