Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles

• Péter Kisszékelyi and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44

Architecture and synthesis of P,N-heterocyclic phosphine ligands

• Wisdom A. Munzeiwa,
• Bernard Omondi and
• Vincent O. Nyamori

Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35

• dimethylamine or, by using ferrocenyl(dimethylamino)acetonitrile. The phosphine group is introduced by ortho-lithiation of the ferrocenylamine followed by subsequent trapping with chlorophosphine [114][115]. Preceding the ground breaking work by Pfaltz, many P,N ligands have been prepared for asymmetric

Synthesis of non-racemic 4-nitro-2-sulfonylbutan-1-ones via Ni(II)-catalyzed asymmetric Michael reaction of β-ketosulfones

• Alexander N. Reznikov,
• Anastasiya E. Sibiryakova,
• Marat R. Baimuratov,
• Eugene V. Golovin,
• Victor B. Rybakov and
• Yuri N. Klimochkin

Beilstein J. Org. Chem. 2019, 15, 1289–1297, doi:10.3762/bjoc.15.127

• transition metal complexes. The preparation of hydroxy sulfones from β-ketosulfones in the presence of Ru [19][20], Ir [21] and Rh [22] complexes was described. Chiral sulfones were also obtained by hydrogenation of the C=C bond with α,β-unsaturated sulfones in the presence of Ir(I) complexes with P,N

• -ligands [23]. The asymmetric addition of various nucleophiles to unsaturated sulfones is also considered as an effective route to chiral sulfones. The conjugated addition of arylboronic acids to unsaturated sulfones under catalysis of Rh complexes was reported [24][25][26]. It was shown that arylboronic

A modular approach to neutral P,N-ligands: synthesis and coordination chemistry

• Vladislav Vasilenko,
• Torsten Roth,
• Clemens K. Blasius,
• Sebastian N. Intorp,
• Hubert Wadepohl and
• Lutz H. Gade

Beilstein J. Org. Chem. 2016, 12, 846–853, doi:10.3762/bjoc.12.83

• neutral κ2-P,N-ligands comprising an imine and a phosphine binding site. These ligands were reacted with rhodium, iridium and palladium metal precursors and the structures of the resulting complexes were elucidated by means of X-ray crystallography. We observed that subtle changes of the ligand backbone

• have a significant influence on the binding geometry und coordination properties of these bidentate P,N-donors. Keywords: P,N-ligands; phosphanylformamidines; phosphine imines; transition metal complexes; Introduction P,N-ligands have been applied in a wide variety of chemical reactions ranging from

• ][10], we have explored three different possibilities to expand the portfolio of P,N-ligands (L1–L3, Figure 1). We reasoned that suitable candidates should be accessible on a multigram scale in excellent yields starting from commercially available reagents and ideally involving a maximum of two steps

Synthesis of 1-[bis(trifluoromethyl)phosphine]-1’-oxazolinylferrocene ligands and their application in regio- and enantioselective Pd-catalyzed allylic alkylation of monosubstituted allyl substrates

• Zeng-Wei Lai,
• Rong-Fei Yang,
• Ke-Yin Ye,
• Hongbin Sun and
• Shu-Li You

Beilstein J. Org. Chem. 2014, 10, 1261–1266, doi:10.3762/bjoc.10.126

• Pd-catalyzed allylic alkylation reaction. Excellent results were obtained for the bulky and electron-rich aryl allyl substrates [25][26][27]. In 2001, Dai, Hou and their coworkers synthesized a new class of 1,1’-ferrocene-based P,N-ligands, namely SiocPhox. The application of these SiocPhox ligands

• an elegant synthesis of bis(perfluoroalkyl)phosphine-oxazoline ligands where small but strongly electron-withdrawing substituents were introduced at the phosphorus [34]. 1,2-Ferrocene based P,N-ligands were synthesized and gave excellent regio- and enantioselectivities in the Pd-catalyzed allylic

Enantioselective synthesis of planar chiral ferrocenes via palladium-catalyzed annulation with diarylethynes

• Yan-Chao Shi,
• Rong-Fei Yang,
• De-Wei Gao and
• Shu-Li You

Beilstein J. Org. Chem. 2013, 9, 1891–1896, doi:10.3762/bjoc.9.222

• -catalyzed direct coupling of N,N-disubstituted aminomethylferrocenes with diarylethyne into an enantioselective reaction. Then planar chiral ferrocenyl P,N-ligands with a large substituent could be readily synthesized. In this paper, we report the results from this study. Results and Discussion We initiated

Palladium-catalyzed dual C–H or N–H functionalization of unfunctionalized indole derivatives with alkenes and arenes

• Gianluigi Broggini,
• Egle M. Beccalli,
• Andrea Fasana and
• Silvia Gazzola

Beilstein J. Org. Chem. 2012, 8, 1730–1746, doi:10.3762/bjoc.8.198

• [PdCl(π-allyl)]2 as the catalyst and Li2CO3 in CH2Cl2 in the presence of C1- and C2-symmetrical P/P and P/N ligands to yield 4-vinyl-tetrahydro-β-carbolines 34 (Scheme 18) [75][76]. The best results in terms of enantioselectivity were achieved by using 35 as a ligand, which provided products with (R

Screening of ligands for the Ullmann synthesis of electron-rich diaryl ethers

• Nicola Otto and
• Till Opatz

Beilstein J. Org. Chem. 2012, 8, 1105–1111, doi:10.3762/bjoc.8.122

• -butylimidazole proved to be the most efficient ligands for Ullmann diaryl ether formation under the tested conditions. The synthesized phosphinite-type P,N-ligands derived from 8-hydroxyquinoline performed well in the short-term screening but lost catalytic activity over time. While active ligands were found in

Electronic differentiation competes with transition state sensitivity in palladium- catalyzed allylic substitutions

• Dominik A. Lange and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2007, 3, No. 36, doi:10.1186/1860-5397-3-36

• -memory effects. [42][43] Computational model systems for P,N-ligands, i.e. PH3 and para-substituted pyridines, have shown that cis-trans differentiations, i.e. the electronic site selectivity, of nucleophilic additions to Pd-η3-allylic intermediates is highest for electron poor pyridine ligands.[45] To

• differentiations provide the basis for the high selectivity of P,N-ligands in Pd-catalyzed allylic substitutions. Effects are studied with P-N-model ligands with para-substituted, coplanar phosphabenzene and pyridine moieties. Activation (ΔEa) and reaction (ΔEr) energies (kcal mol-1), computed for the P,N-ligand

• of substrate and catalyst structures. "Side arm guidance" of nucleophiles with multifunctional phosphinoferrocenes [14][15][16][17][18] or "chiral pockets" in C2-symmetric diphosphanes based on 2-(diphenyl-phosphino)benzoic acid amides [19][20][21][22] were applied especially successfully. Chiral P,N

A superior P-H phosphonite: Asymmetric allylic substitutions with fenchol- based palladium catalysts

• Bernd Goldfuss,
• Thomas Löschmann,
• Tina Kop-Weiershausen,
• Jörg Neudörfl and
• Frank Rominger

Beilstein J. Org. Chem. 2006, 2, No. 7, doi:10.1186/1860-5397-2-7

• Pamies et al. (Scheme 2) [7]. Besides bidentate P, N-ligands, monodentate ligands are useful, as was demonstrated successfully by Hayashi et al. with the MeO-MOP ligand, yielding 90% branched product with 87% ee for a C-methylated malonate nucleophile and the 4-methoxyphenylallyl substrate [8]. Van

• ). Bidentate P, N-ligands and a monodentate phosphoramidite for Pd-catalyzed allylic substitutions with unsymmetric substrates, cf. Scheme 1. Fenchole-based phosphorus ligands (i.e. FEENOPs and BIFOPs) for Pd-catalyzed allylic substitutions. Pd-π arene or Pd-N coordinations give rise to different