Phosphinofenchol or Metastable Phosphorane? Phosphorus Derivatives of Fenchol

Goldfuß, Bernd; Löschmann, Thomas; Röminger, Frank

doi:10.1002/1521-3765(20010601)7:11<2284::aid-chem22842>3.0.co;2-v

Cited by 3 publications

(2 citation statements)

References 13 publications

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“…The steric hindrance of the reaction centre can significantly affect the stereoselectivity of the reaction. Various derivatives with bornane backbone have found applications as efficient organocatalysts in Pd‐catalyzed alkylation, [10] asymmetric Michael addition, [11] and asymmetric cyclopropanation [12]…”

Section: Introductionmentioning

confidence: 99%

Facile Stereoselective Synthesis and Structural Study of Camphor‐ and Fenchone‐Based Spirocyclic 1,3,4‐Oxadiazolines

Kovaleva,

Abdrakhmanova,

Yarovaya

et al. 2023

Eur J Org Chem

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For the first time, an effective method for the synthesis of spirocyclic camphor‐ and fenchone‐based 1,3,4‐oxadiazolines has been developed. The influence of the molecular structure of the terpene substrate on the reaction stereoselectivity was studied. The structural features of the target products were studied using NMR spectroscopy and X‐ray diffraction analysis. The proposed method allows obtaining of spirocyclic products with a wide structural diversity, stereoselectively and in good yields.

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Section: Introductionmentioning

confidence: 99%

Facile Stereoselective Synthesis and Structural Study of Camphor‐ and Fenchone‐Based Spirocyclic 1,3,4‐Oxadiazolines

Kovaleva,

Abdrakhmanova,

Yarovaya

et al. 2023

Eur J Org Chem

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“…Modular fencholates were recently applied in chiral organolithium reagents [ 53 - 59 ] and in organozinc [ 60 - 63 ] as well as in organopalladium catalysts [ 64 - 68 ] to study origins of enantioselectivities in C-C-couplings. The rigid, terpene-based bicyclo[2.2.1]heptane unit enables efficient, stereoselective access to crystalline diol ligands such as BIFOL ( bi phenyl-bis f ench ol ), [ 69 - 73 ] which we here apply for constructions of new BIFOL-based, phosphorus ligands, i.e.…”

Section: Introductionmentioning

confidence: 99%

An exceptional P-H phosphonite: Biphenyl-2,2'-bisfenchylchlorophosphite and derived ligands (BIFOPs) in enantioselective copper-catalyzed 1,4-additions

Kop-Weiershausen

Lex

Neudörfl

et al. 2005

Beilstein J. Org. Chem.

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Biphenyl-2,2'-bisfenchol (BIFOL) based chlorophosphite, BIFOP-Cl, exhibits surprisingly high stabilities against hydrolysis as well as hydridic and organometallic nucleophiles. Chloride substitution in BIFOP-Cl proceeds only under drastic conditions. New enantiopure, sterically demanding phosphorus ligands such as a phosphoramidite, a phosphite and a P-H phosphonite (BIFOP-H) are hereby accessible. In enantioselective Cu-catalyzed 1,4-additions of ZnEt 2 to 2-cyclohexen-1-one, this P-H phosphonite (yielding 65% ee) exceeds even the corresponding phosphite and phosphoramidite.

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Ligand Bite Governs Enantioselectivity: Electronic and Steric Control in Pd‐Catalyzed Allylic Alkylations by Modular Fenchyl Phosphinites (FENOPs)

Goldfuß

Löschmann²,

Röminger

2004

Chemistry A European J

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Modular fenchyl phosphinites (FENOPs) containing different aryl units-phenyl (1), 2-anisyl (2), or 2-pyridyl (3)-are efficiently accessible from (-)-fenchone. For comparison of the influence of the different aryl units on enantioselectivities and reactivities, these FENOPs were employed in Pd-catalyzed allylic alkylations. The strongly chelating character of P,N-bidentate 3 is apparent from X-ray structures with PdCl2 ([Pd3Cl2]), and with allyl-Pd units in ([Pd3(eta1-allyl)] and [Pd3(eta3-allyl)]). FENOP3 gives rise to a PdL* catalyst of moderate enantioselectivity (42 % ee, R product). Surprisingly, higher enantioselectivities are found for the hemilabile, monodentate FENOPs 1 (83 % ee, S enantiomer) and 2 (69 % ee, S enantiomer). Only small amounts of 1 or 2 generate selective PdL* catalysts, while complete abolition of enantioselectivity appears with unselective PdL*2 species with higher FENOP concentrations in the cases of 1 or 2. Computational transition structure analyses reveal steric and electronic origins of enantioselectivities. The nucleophile is electronically guided trans to phosphorus. endo-Allyl arrangements are favored over exo-allyl orientations for 1 and 2 due to Pd-pi-pyridyl interactions with short "side-on" Pd-aryl interactions. More remote "edge-on" Pd-pi-aryl interactions in 3 with Pd-N(lp) coordination favor endo-allyl units slightly more and explain the switch of enantioselectivity from 1 (S) and 2 (S) to 3 (R).

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Phosphinofenchol or Metastable Phosphorane? Phosphorus Derivatives of Fenchol

Cited by 3 publications

References 13 publications

Facile Stereoselective Synthesis and Structural Study of Camphor‐ and Fenchone‐Based Spirocyclic 1,3,4‐Oxadiazolines

Facile Stereoselective Synthesis and Structural Study of Camphor‐ and Fenchone‐Based Spirocyclic 1,3,4‐Oxadiazolines

An exceptional P-H phosphonite: Biphenyl-2,2'-bisfenchylchlorophosphite and derived ligands (BIFOPs) in enantioselective copper-catalyzed 1,4-additions

Ligand Bite Governs Enantioselectivity: Electronic and Steric Control in Pd‐Catalyzed Allylic Alkylations by Modular Fenchyl Phosphinites (FENOPs)

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