Stereospecific functionalization of (R)-(−)-1,1′-bi-2-naphthol triflate

Kurz, Lilia J.; Lee, Gary; Morgans, David J.; Waldyke, Michael Joe; Ward, Timothy L.

doi:10.1016/s0040-4039(00)97053-9

Cited by 121 publications

(62 citation statements)

References 36 publications

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“…Thus we sought to prepare previously inaccessible ligands via functionalization of the phosphorus hydrogen bonds. [51] and are typically somewhat restricted in type by their formulation from the secondary phosphine or secondary phosphine oxide precursors [52,53]. In a number of catalytic transformations, the available MOP ligands do not provide optimum levels of conversion or enantioselectivity, whilst (R)-MOP itself is also rather expensive [54][55][56].…”

Section: Reactivity Of the Air-stable Primary Phosphinesmentioning

confidence: 99%

The Primary Phosphine Renaissance

Higham¹

2011

Phosphorus Compounds

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Primary phosphines are renowned for being toxic, volatile, pyrophoric compounds which have to be handled under an inert atmosphere due to their ease of air-oxidation. Thus despite numerous potential applications, they remain underutilized precursors in synthetic chemistry. Only a small number of air-stable primary phosphines are known, and their stability is either attributable to high steric hindrance about the phosphino group or the underlying factors are as yet undetermined. This work is an account of the recent studies carried out by our research group and presents a new family of air-stable chiral primary phosphines (R)-5 and (S)-6 based on the binaphthyl backbone. The stabilization is a result of p-conjugation and is discussed with reference to naphthyl-and phenyl-based analogues. Computational studies based on the DFT B3LYP/6-31G* level of theory suggests significant p-conjugation or sufficient heteroatom presence dislocates the phosphorus away from the HOMO of the ground state and raises the energy of the HOMO in the associated radical cation, with a threshold of stability emerging. Novel phosphonites, phospholanes and bis(hydroxymethyl)phosphines were synthesized from (R)-5 and (S)-6 and tested in the catalytic asymmetric hydrosilylation of styrene.

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Section: Reactivity Of the Air-stable Primary Phosphinesmentioning

confidence: 99%

The Primary Phosphine Renaissance

Higham¹

2011

Phosphorus Compounds

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“…To enhance efficiency of the C À P bond formation (Scheme 1), other supporting ligands than triphenylphosphine used by Hirao et al, [1] were investigated [for example, dppp, [16] dppb, [17] PPh 2 (m-C 6 H 4 SO 3 M) [18] ], and the most efficient was found to be a wide-bite-angle ligand, [19] 1,1'-bis(diphenylphosphino)ferrocene (dppf). [12,[20][21][22] In this type of crosscoupling reactions the base has to be used in a stoichiometric amount.…”

Section: Introductionmentioning

confidence: 99%

Preparation of Arylphosphonates by Palladium(0)‐Catalyzed Cross‐Coupling in the Presence of Acetate Additives: Synthetic and Mechanistic Studies

Kalek¹,

Jezowska²,

Stawiński³

2009

Adv Synth Catal

147

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An efficient protocol for the synthesis of arylphosphonate diesters via a palladium-catalyzed cross-coupling of H-phosphonate diesters with aryl electrophiles, promoted by acetate ions, was developed. A significant shortening of the cross-coupling time in the presence of the added acetate ions was achieved for bidentate and monodentate supporting ligands, and for different aryl electrophiles (iodo, bromo and triflate derivatives). The reaction conditions were optimized in terms of amount of the catalyst, supporting ligands, and source of the acetate ion used. Various arylphosphonates, including those of potential biological significance, were synthesized using this newly developed protocol. Some mechanistic aspects of the investigated reactions are also discussed.

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“…Thus, the reaction of 2-methoxycarbonyl-1-bromonaphthalene (1 dBr) with 2 A gave 2-methoxycarbonyl-2'-methyl-1,1'-binaphthyl (3 dA) in 61 % yield with 88 % ee ( Table 1, entry 10). The reaction of phosphonate 1 e-Br with 2 B afforded diethyl 2'-methoxy-1,1'-binaphth-2-yl phosphonate (3 eB), a synthetic precursor of 2-diphenylphosphanyl-1,1'-binaphthyl (MOP) ligands, [11] in 70 % yield as a white precipitate. The enantiomeric purity of 3 eB was increased through crystallization to 99 % ee (Table 1, entry 11).…”

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confidence: 99%