- Palladium-Catalyzed Enantioselective C(sp3)-H Arylation of 2-Propyl Azaaryls Enabled by an Amino Acid Ligand
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A palladium(II)-catalyzed enantioselective arylation of unbiased secondary C(sp3)-H bonds was developed. The enantioselectivity was controlled by the combination of a pyridyl or isoquinolinyl directing group and an amino acid, N-Boc-2-pentyl proline. A variety of 2-propyl azaaryls and biaryl iodides were employed to provide arylated products in moderate to good yields (up to 82%) with high enantioselectivities (up to 93:7 er). This reaction is a rare example of an amino-acid-enabled enantioselective acyclic methylene C(sp3)-H arylation. Furthermore, the reaction proceeded with high enantioselectivity even on a gram scale, and the product was transformed to a 5,6,7,8-tetrahydroisoquinoline bioactive molecule. Kinetic isotope effect (KIE) experiments indicated that C-H activation is the rate-determining step for the enantioselective C(sp3)-H arylation.
- Antilla, Jon C.,Jing, Hua-Qing,Kuninobu, Yoichiro,Li, Hong-Liang,Yang, Deng-Feng
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p. 1286 - 1291
(2022/02/25)
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- Asymmetric Lewis acid mediated [1,2]-rearrangement of proline-derived ammonium ylides
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The first example of asymmetric Lewis acid mediated [1,2]-rearrangement of N-benzylic proline amides to form quaternary proline derivatives is reported. The presented reaction is shown to proceed with remarkable high C→N→C chirality transfer. Various quat
- Tuzina, Pavel,Somfai, Peter
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supporting information; experimental part
p. 919 - 921
(2009/08/15)
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- Highly enantioselective synthesis of rigid, quaternary 1,4-benzodiazepine- 2,5-diones derived from proline
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(Chemical Equation Presented) Proline-derived 1,4-benzodiazepine-2,5-diones are extremely useful scaffolds in medicinal chemistry. In this paper, we describe a protocol for retentive C3 alkylation of these materials, thus accomplishing the direct synthesis of enantiopure quaternary 1,4-benzodiazepine-2,5-diones. The high enantioselectivities (up to 99.5%) are attributed to memory of chirality.
- MacQuarrie-Hunter, Stephanie,Carlier, Paul R.
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p. 5305 - 5308
(2007/10/03)
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- An improved method of oxazolidinone hydrolysis in the asymmetric synthesis of α-alkylprolines
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An improvement in Seebach's method for the synthesis of α-alkylprolines is reported wherein the hydrolysis of the chiral oxazolidinone 2 is performed on a suspension of silica gel in MeOH/H2O. Following hydrolysis, the pure α-alkylproline can be obtained by filtration thereby avoiding a tedious ion exchange purification.
- Genin, Michael J.,Baures, Paul W.,Johnson, Rodney L.
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p. 4967 - 4968
(2007/10/02)
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