Catalytic Enantioselective Synthesis of α-Aminooxy and α-Hydroxy Ketone Using Nitrosobenzene
摘要:
The highly enantioselective and O-selective nitroso aldol reaction of tin enolates 2 and nitrosobenzene (1) has been developed with the use of (R)-BINAP-silver complexes as a catalyst. After the various silver salts were surveyed, the AgOTf and the AgClO4 complex were found to be optimal in the O-selective nitroso aldol reaction in both asymmetric induction (up to 97% ee) and regioselection (O/N = >99/1), affording aminooxy ketone 3. The product 3 can be transformed to alpha-hydroxy ketone 5 without any loss of enantioselectivity. Thus, the method provides an efficient approach to the catalytic enantioselective introduction of oxygen alpha- to the carbonyl group.
Dibutyltin dimethoxide-catalyzed aldol reaction of enol trichloroacetates
作者:Akira Yanagisawa、Takayuki Sekiguchi
DOI:10.1016/s0040-4039(03)01840-9
日期:2003.9
A catalytic aldol condensation of aldehydes with enol trichloroacetates was achieved usingdibutyltindimethoxide as a novel catalyst in a mixed solvent consisting of THF and MeOH. Various β-hydroxy ketones were diastereoselectively obtained in high yields up to 99%.
Catalytic Asymmetric Cycloaddition Reaction of Alkenyl Trichloroacetates with Nitrones
作者:Akira Yanagisawa、Atsuto Izumiseki、Takuya Sugita、Naoyuki Kushihara、Kazuhiro Yoshida
DOI:10.1055/s-0031-1290094
日期:2012.1
(S)-BINOL-derived chiral tindibromide possessing a 4-trifluoromethylphenyl group at 3- and 3′-positions as the chiral precatalyst in the presence of sodium ethoxide, sodium iodide, and ethanol. Optically active isoxazolidines with up to 95% ee were diastereoselectively obtained in high yields even from aliphatic aldehyde derived nitrones under the influence of the in situ generated chiral tin ethoxide iodide
Catalytic Enantioselective Mannich-Type Reaction via a Chiral Silver Enolate
作者:Akira Yanagisawa、Yuqin Lin、Ryoji Miyake、Kazuhiro Yoshida
DOI:10.1021/ol403075u
日期:2014.1.3
A catalytic asymmetric Mannich-typereaction of alkenyl trichloroacetates with aldimines was achieved using SEGPHOS·AgOTf as the chiral precatalyst and N,N-diisopropylethylamine as the base precatalyst in the presence of 2,2,2-trifluoroethanol. Optically active β-amino ketones with up to >99% ee were syn-selectively obtained in moderate to high yields via the in situ generated chiral silver enolates
Asymmetric Aldol Reaction of Alkenyl Esters with α-Keto Esters Catalyzed by Chiral Tin Alkoxides
作者:Akira Yanagisawa、Chika Uchiyama、Kotaro Takagi
DOI:10.1055/a-1665-9014
日期:2021.12
A catalytic enantioselective aldol reaction of alkenyl esters with α-ketoesters was achieved by using an (R)-BINOL-derived chiral tin dibromide possessing 4-t-butylphenyl groups at the 3- and 3′-positions as a chiral precatalyst in the presence of sodium methoxide and methanol. Optically active aldol products possessing a chiral tertiary carbon were diastereoselectively obtained with up to 92% ee
Asymmetric Aldol Reaction Catalyzed by a Chiral Phosphine-Silver Complex
作者:Akira Yanagisawa、Ryoji Miyake、Kazuhiro Yoshida
DOI:10.1002/ejoc.201402351
日期:2014.7
A catalytic asymmetricaldolreaction of alkenyl trihaloacetates or a γ,δ-unsaturated δ-lactone with aldehydes or an α-ketoester was achieved by using a 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl·silver trifluoromethanesulfonate complex as the chiral precatalyst and N,N-diisopropylethylamine as the base precatalyst in the presence of methanol. Optically active α-alkyl β-hydroxy ketones with enantioselectivities
通过使用 2,2'-双(二苯基膦)-1,1'-联萘·三氟甲磺酸银实现了烯基三卤乙酸酯或 γ,δ-不饱和 δ-内酯与醛或 α-酮酯的催化不对称醛醇反应在甲醇存在下,络合物作为手性预催化剂,N,N-二异丙基乙胺作为碱预催化剂。通过原位生成的手性银烯醇化物,以中等至高产率非对映选择性地获得了对映选择性高达 95% ee 的光学活性 α-烷基 β-羟基酮。