16635-23-7Relevant articles and documents
Organotitanium nucleophiles in asymmetric cross-coupling reaction: Stereoconvergent synthesis of chiral α-cf3 thioethers
Varenikov, Andrii,Gandelman, Mark
, p. 10994 - 10999 (2019)
Asymmetric Ni-catalyzed cross-coupling reactions have become a very attractive tool for the stereoselective construction of valuable organic chiral materials. While various nucleophiles are used in such transformation, organotitanium(IV) has not been used before. Herein we demonstrate, for the first time, that organotitanium species can serve as efficient coupling partners in asymmetric cross-couplings, which have proven to be beneficial, compared to the commonly used organomagnesium and organozinc counterparts. This principle is exemplified by the first asymmetric catalytic synthesis of CF3-substituted thioethers via a Ni-catalyzed stereoconvergent cross-coupling reaction. Thioether moieties and their derivatives are common motifs in many biologically active compounds, and their enantioenriched fluorinated analogs should be of great interest in the search for novel drugs and agrichemicals.
Synthesis of Chiral α-CF3-Substituted Benzhydryls via Cross-Coupling Reaction of Aryltitanates
Varenikov, Andrii,Shapiro, Evgeny,Gandelman, Mark
supporting information, p. 9386 - 9391 (2020/12/21)
We describe a highly efficient approach toward α-CF3-substituted benzhydryls thanks to the employment of organotitanium(IV) based nucleophiles. The use of commercially available anesthetic halothane as a cheap fluorinated building block in a sequential one-pot nickel-catalyzed enantioselective cross-coupling reaction of aryl titanates allowed for the synthesis of chiral α-CF3-substituted benzhydryls in good yields and excellent enantioselectivities. Alternatively, α-CF3-benzyl bromides could be employed under similar conditions to obtain the same family of compounds in higher yields and excellent selectivities. A benzhydryl moiety is a common motif in many biologically active compounds, and their enantioenriched fluorinated analogs should be of great interest in the search for novel drugs and agrochemicals.
Catalytic Enantioselective Arylation and Heteroarylation of Ketones with Organotitanium Reagents Generated In Situ
Matsuda, Atsushi,Ushimaru, Tomoya,Kobayashi, Yusuke,Harada, Toshiro
supporting information, p. 8605 - 8609 (2017/06/30)
A practical and useful, catalytic enantioselective method has been developed for the synthesis of tertiary diaryl and aryl heteroaryl carbinols starting from commercially available aromatic ketones and aryl or heteroaryl bromides. In this method, organotitanium reagents are generated in situ from the bromides by lithiation with nBuLi followed by transmetallation of the resulting organolithiums with ClTi(OiPr)3. Treatment of the ketones with the titanium reagents in the presence of (R)-3-(3,5-bistrifluoromehthylphenyl)-1,1′-bi-2-naphthol (BTFP-BINOL) affords the corresponding tertiary alcohols in high enantioselectivities and yields. The reaction can also start with furan and 2-thienyllithium. The method is operationally simple and can be conducted on a 10-mmol scale without any difficulties.
