Synthesis of a new chiral source, (1R,2S)-1-Phenylphospholane-2-carboxylic acid, via a key intermediate alpha-phenylphospholanyllithium borane complex: configurational stability and X-ray crystal structure of an alpha-monophosphinoalkyllithium borane complex

Efficient Oxidative Resolution of 1-Phenylphosphol-2-Ene and Diels–Alder Synthesis of Enantiopure Bicyclic and Tricyclic P-Stereogenic C-P Heterocycles

1-Phenylphosphol-2-ene 1-oxide is effectively resolved by L-menthyl bromoacetate to afford both SP and RP enantiomers of 1-phenylphosphol-2-ene 1-oxide on a multigram scale. The resolved 1-phenylphosphol-2-ene oxide has been found to undergo face-selective and endo-selective cycloadditions with a series of acyclic and cyclic dienes to produce enantiopure P-stereogenic C-P heterocycles of hexahydrophosphindole and hexahydrobenzophosphindole as well as phospha[5.2.1.02,6]decene and phospha[5.2.2.02,6]undecene structures. Conversions of these cycloadducts to the fully saturated heterocyclic systems as well as to their P (III), P = S, P = Se and P-BH3 derivatives have been demonstrated to occur with retention of configuration and preservation of configurational homogeneity at P. A perplexing case of stereomutation at P during reduction of a tricyclic β-hydroxy phosphine oxide by PhSiH3 at 80 °C has been recorded.

Phosphacycloalkyldiones: synthesis and coordinative behaviour of 6- and 7-member cyclic diketophosphanyls

Condensation of glutaryl and adipoyl chlorides with bis(silyl)phosphanes RP(SiMe₃)₂ (R = Me, ⁿBu, ^tBu, Ph, Mes) affords the conformationally fluxional phosphacycloalkyldiones (CH₂)_n(CO)₂PR (n = 3, 4); their coordination behaviour is explored.

Design, synthesis and application of a new type of bifunctional in highly enantioselective γ-addition reactions of N-centered nucleophiles to allenoates

A novel class of cyclic phosphine derived bifunctional catalysts (Le-Phos) is reported, which can be readily prepared from inexpensive and commercially available starting materials and exhibit good performances in enantioselective γ-addition reactions of N-centered nucleophiles and allenoates under mild conditions. The salient features of this reaction include high product yields, good enantioselectivity, mild reaction conditions, and broad substrate scope and gram-scale scalability.

Intramolecular Nucleophilic Substitution of ω-Haloalkylphosphine Derivatives

ω-Haloalkylphosphine derivatives undergo the intramolecular nucleophilic substitution reaction upon treatment with a strong base, yielding either cycloalkylphosphine derivatives or heterocyclic phosphine derivatives. The selectivity of the cyclization of (ω-haloalkyl)alkylarylphosphine derivatives depends strongly on the distance between the electrophilic and nucleophilic carbon atoms and the structure of the phosphorus moiety. The desymmetrization of dimethylphenylphosphine sulfide followed by haloalkylation and cyclization led to the enantiomerically enriched tertiary phosphine sulfide, possessing a cyclohexyl fragment at the phosphorus.

Resolution of P-stereogenic P-heterocycles via the formation of diastereomeric molecular and coordination complexes (a review)

TADDOL derivatives and the Ca²⁺-salts of tartaric acid derivatives were found to be versatile and generally applicable resolving agents for the preparation of the enantiomers of P-stereogenic heterocyclic phosphine oxides and phosphinates.

Borane as an efficient directing group. Stereoselective 1,2-addition of organometallic reagents to borane P-stereogenic N-phosphanylimines

The 1,2-addition of organolithium reagents to borane P-stereogenic N-phosphanylimines was found to be a highly selective solvent-dependent stereodivergent process.

Synthesis, characterization and reactivity of potassium and barium complexes containing phosphane-borane stabilized methanides

The polymeric potassium complex [K{CH(PPh2BH3)2}]∞ (1) was prepared and used as a starting material for the syntheses of related N,N,N',N'-tetramethylethylenediamine (tmeda) and N,N,N',N',N''-pentamethyldiethylenetriamine (pmdta) ligated potassium derivatives [K{CH(PPh2BH3)2}(tmeda)2]∞ (2) and [K{CH(PPh2BH3)2}(pmdta)]2 (3). Salt metathesis reactions with [BaI2(thf)5] allowed the synthesis of the barium derivatives [BaI{CH(PPh2BH3)2}(thf)5] (5) and [Ba{CH(PPh2BH3)2}2(solv)2}] (solv = Et2O, thf) (6), which are more prone to subsequent reactions than the potassium derivatives. One of the resulting products, [Ba4O{CH(PPh2BH3)2}3{Ph2PCH(BH3)PPh2BH3}3] (7), which contains two different isomeric forms of the bis(borane) adduct of Ph2PCHPPh2, was isolated. The complexes were characterized by NMR techniques and single crystal X-ray diffraction measurements.

Recent advances in the application of chiral phosphine ligands in Pd-catalysed asymmetric allylic alkylation

One of the most powerful approaches for the formation of simple and complex chiral molecules is the metal-catalysed asymmetric allylic alkylation. This reaction has been broadly studied with a great variety of substrates and nucleophiles under different reaction conditions and it has promoted the synthesis of new chiral ligands to be evaluated as asymmetric inductors. Although the mechanism as well as the active species equilibria are known, the performance of the catalytic system depends on the fine tuning of factors such as type of substrate, nucleophile nature, reaction medium, catalytic precursor and type of ligand used. Particularly interesting are chiral phosphines which have proved to be effective asymmetric inductors in several such reactions. The present review covers the application of phosphine-donor ligands in Pd-catalysed asymmetric allylic alkylation in the last decade.

Alkali metal complexes of a phosphine–borane-stabilised carbanion: influence of co-ligands on structure

The adducts [[(Me(3)Si)(2){Me(2)P(BH(3))}C]K(L)(n)](m) [L = THF, n = 0.5, m = infinity (2a); L = tmeda (2b), pmdeta (2c), n = 1, m = 2] may be synthesised by treatment of solvent-free [[(Me(3)Si)(2){Me(2)P(BH(3))}C]K](infinity) (2) with the corresponding Lewis base (tmeda = N,N,N',N'-tetramethylethylenediamine; pmdeta = N,N,N',N'',N''-pentamethyldiethylenetriamine). X-Ray crystallography reveals that, whereas 2 crystallises with a complex 2-dimensional sheet structure, 2a crystallises as a ribbon-type one-dimensional polymer and both 2b and 2c crystallise as dimers. The corresponding complex with 12-crown-4, [K(12-crown-4)(2)][(Me(3)Si)(2){Me(2)P(BH(3))}C] (2d) crystallises as a separated ion pair. The complexes [[(Me(3)Si)(2){Me(2)P(BH(3))}C]M(pmdeta)](n) [M = Na, n = 1 (6); M = Rb, n = 2 (7)] may be synthesised by treatment of [(Me(3)Si)(2){Me(2)P(BH(3))}C]M with pmdeta. Whereas crystallises as a discrete monomer, compound 7 crystallises as a dimer. Compounds 2, 2a-2d, 6, 7 and the corresponding caesium derivative [[(Me(3)Si)(2){Me(2)P(BH(3))}C]Cs(pmdeta)](2) () provide an opportunity to consider the influence of the ionic radius of the metal and the nature of the co-ligands on the structures of alkali metal complexes of a phosphine-borane-stabilised carbanion.