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New types of soluble polymer-supported bisphosphine ligands with a cyclobutane backbone for Pd-catalyzed enantioselective allylic substitution reactions.
Chemistry. 2004 Nov 19; 10(23):5952-63.C

Abstract

A highly efficient and practical optical resolution of anti head-to-head racemic coumarin dimer 7 has been achieved by molecular complexation with TADDOL, (-)-8, through a hydrogen bonding interaction to afford the corresponding two enantiomers, (-)- and (+)-7, in 70 and 75 % yields, respectively, with >99 % ee. Starting from enantiopure (-)-7, a new type of C2-symmetric bisphosphine ligand (S,S,S,S)-3 with a cyclobutane backbone has been synthesized in good yield by facile transformations. The asymmetric induction efficiency of these chiral bisphosphine ligands in Pd-catalyzed asymmetric allylic substitution reactions was evaluated. Under the experimental conditions, the allylic substitution products could be obtained in excellent yields (up to 99 %) and enantioselectivities (up to 98.9 % ee). By taking advantage of the high enantioselectivity of this catalytic reaction and the easily derivable carboxylate groups on the cyclobutane backbone of ligand (S,S,S,S)-3, a new type of analogous ligand (S,S,S,S)-4 as well as the MeO-PEG-supported soluble ligand (S,S,S,S)-5 (PEG=polyethylene glycol) have also been synthesized and utilized in asymmetric allylic substitution reactions. In particular, the MeO-PEG supported (S,S,S,S)-5 b had a synergistic effect on the enantioselectivity of the reaction compared with its nonsupported precursor (S,S,S,S)-4 c, affording the corresponding allylation products 14 a and 14 b with excellent enantioselectivities (94.6 and 97.2 % ee, respectively). Moreover, the Pd complex of (S,S,S,S)-5 b could easily be recovered and recycled several times without significant loss of enantioselectivity and activity in the allylic substitution reactions.

Authors+Show Affiliations

Zhao D
State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032, China.
Sun J
No affiliation info available
Ding K
No affiliation info available

MeSH

Allyl CompoundsAnticoagulantsCatalysisCoumarinsCyclobutanesDimerizationLigandsOrganometallic CompoundsPalladiumPhosphinesPolymersSolubilityStereoisomerism

Pub Type(s)

Journal Article

Language

eng

PubMed ID

15487028

Citation

Zhao, Dongbo, et al. "New Types of Soluble Polymer-supported Bisphosphine Ligands With a Cyclobutane Backbone for Pd-catalyzed Enantioselective Allylic Substitution Reactions." Chemistry (Weinheim an Der Bergstrasse, Germany), vol. 10, no. 23, 2004, pp. 5952-63.
Zhao D, Sun J, Ding K. New types of soluble polymer-supported bisphosphine ligands with a cyclobutane backbone for Pd-catalyzed enantioselective allylic substitution reactions. Chemistry. 2004;10(23):5952-63.
Zhao, D., Sun, J., & Ding, K. (2004). New types of soluble polymer-supported bisphosphine ligands with a cyclobutane backbone for Pd-catalyzed enantioselective allylic substitution reactions. Chemistry (Weinheim an Der Bergstrasse, Germany), 10(23), 5952-63.
Zhao D, Sun J, Ding K. New Types of Soluble Polymer-supported Bisphosphine Ligands With a Cyclobutane Backbone for Pd-catalyzed Enantioselective Allylic Substitution Reactions. Chemistry. 2004 Nov 19;10(23):5952-63. PubMed PMID: 15487028.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - New types of soluble polymer-supported bisphosphine ligands with a cyclobutane backbone for Pd-catalyzed enantioselective allylic substitution reactions. AU - Zhao,Dongbo, AU - Sun,Jie, AU - Ding,Kuiling, PY - 2004/10/16/pubmed PY - 2006/5/26/medline PY - 2004/10/16/entrez SP - 5952 EP - 63 JF - Chemistry (Weinheim an der Bergstrasse, Germany) JO - Chemistry VL - 10 IS - 23 N2 - A highly efficient and practical optical resolution of anti head-to-head racemic coumarin dimer 7 has been achieved by molecular complexation with TADDOL, (-)-8, through a hydrogen bonding interaction to afford the corresponding two enantiomers, (-)- and (+)-7, in 70 and 75 % yields, respectively, with >99 % ee. Starting from enantiopure (-)-7, a new type of C2-symmetric bisphosphine ligand (S,S,S,S)-3 with a cyclobutane backbone has been synthesized in good yield by facile transformations. The asymmetric induction efficiency of these chiral bisphosphine ligands in Pd-catalyzed asymmetric allylic substitution reactions was evaluated. Under the experimental conditions, the allylic substitution products could be obtained in excellent yields (up to 99 %) and enantioselectivities (up to 98.9 % ee). By taking advantage of the high enantioselectivity of this catalytic reaction and the easily derivable carboxylate groups on the cyclobutane backbone of ligand (S,S,S,S)-3, a new type of analogous ligand (S,S,S,S)-4 as well as the MeO-PEG-supported soluble ligand (S,S,S,S)-5 (PEG=polyethylene glycol) have also been synthesized and utilized in asymmetric allylic substitution reactions. In particular, the MeO-PEG supported (S,S,S,S)-5 b had a synergistic effect on the enantioselectivity of the reaction compared with its nonsupported precursor (S,S,S,S)-4 c, affording the corresponding allylation products 14 a and 14 b with excellent enantioselectivities (94.6 and 97.2 % ee, respectively). Moreover, the Pd complex of (S,S,S,S)-5 b could easily be recovered and recycled several times without significant loss of enantioselectivity and activity in the allylic substitution reactions. SN - 0947-6539 UR - https://www.unboundmedicine.com/medline/citation/15487028/New_types_of_soluble_polymer_supported_bisphosphine_ligands_with_a_cyclobutane_backbone_for_Pd_catalyzed_enantioselective_allylic_substitution_reactions_ DB - PRIME DP - Unbound Medicine ER -
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