Palladium-catalyzed stereoretentive olefination of unactivated C(sp3)-H bonds with vinyl iodides at room temperature: Synthesis of β-vinyl α-amino acids
A method is reported for palladium-catalyzed N-quinolyl carboxamide-directed olefination of the unactivated C(sp3)-H bonds of phthaloyl alanine with a broad range of vinyl iodides at room temperature. This reaction represents the first example of the stereoretentive installation of multisubstituted terminal and internal olefins onto unactivated C(sp3)-H bonds. These methods enable access to a wide range of challenging β-vinyl α-amino acid products in a streamlined and controllable fashion, beginning from simple precursors.
Wang, Bo,Lu, Chengxi,Zhang, Shu-Yu,He, Gang,Nack, William A.,Chen, Gong
Amino acid chiral ligand containing bidentate coordination group, chiral catalyst, and corresponding preparation methods and applications thereof
The present invention relates to an amino acid chiral ligand containing a bidentate coordination group, a chiral catalyst, and corresponding preparation methods and applications thereof. The chiral ligand is prepared from a cheap and easily available amino acid, and the development of the chiral ligand can improve the diversity of the chiral ligand. The chiral Ir (III) catalyst is simply and efficiently prepared from the chiral ligand only through a one-step reaction. The chiral Ir (III) catalyst is characterized in that a bidentate guiding group is introduced to an amino acid framework to change the original coordination mode of the amino acid and Ir in order to enhance the chiral control ability of the amino acid to the Ir(III) catalyst. The chiral Ir(III) catalyst is designed and synthesized for the first time, and the selectivity reaches up to 99% ee when the catalyst is successfully applied to the high-efficiency asymmetric synthesis of chiral gamma-cyclolactam, so the catalyst has superior stereo control ability.
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(2019/10/02)
Palladium-catalyzed direct intermolecular silylation of remote unactivated C(sp3)-H bonds
An efficient and convenient method has been developed to achieve direct silylation of unactivated remote primary or secondary C(sp3)-H bonds to form C-Si bonds with hexamethyldisilane (HMDS). This method highlights the emerging strategy to transform unactivated methyl or methylene into versatile functional groups in organic synthesis and provides a new method to construct functionalized C-Si bonds for synthetic chemistry.
Use of a readily removable auxiliary group for the synthesis of pyrrolidones by the palladium-catalyzed intramolecular amination of unactivated γ C(sp3)-H Bonds
Easy on, easy off: Directing groups found to promote the palladium-catalyzed amination of γ C(sp3)-H and C(sp 2)-H bonds of secondary amides included 5-methoxy-8-aminoquinoline, which can be removed under mild conditions (see scheme; CAN=ceric ammonium nitrate). In conjunction with a β-C-H methylation or γ-C-H arylation step, the γ-C(sp3)-H amination provided access to complex pyrrolidones from readily available precursors. Copyright
He, Gang,Zhang, Shu-Yu,Nack, William A.,Li, Qiong,Chen, Gong
p. 11124 - 11128
(2013/10/22)
Nonnatural amino acid synthesis by using carbon-hydrogen bond functionalization methodology
Taking direction well: Substituted phenylalanine derivatives were prepared by C-H bond functionalization (see scheme). The syntheses are highly convergent and employ an N-phthaloylalanine with a 2-thiomethylaniline directing group. The use of an 8-aminoquinoline directing group allows for the diarylation of methyl and the diastereoselective arylation of methylene groups. Copyright
Tran, Ly Dieu,Daugulis, Olafs
p. 5188 - 5191
(2012/07/27)
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