79090-61-2Relevant academic research and scientific papers
Chemo- and Regioselective Functionalization of Polyols through Catalytic C(sp3)-C(sp3) Kumada-Type Coupling of Cyclic Sulfate Esters
Ramírez-Contreras, Rodrigo,Morandi, Bill
, p. 3718 - 3721 (2016/08/16)
This contribution describes a copper-catalyzed, C(sp3)-C(sp3) cross-coupling reaction of cyclic sulfate esters, a distinct class of electrophilic derivatives of polyols, with alkyl Grignard reagents to afford functionalized alcohol products in good yields. The method is operationally simple and highlights the potential of cyclic sulfate esters as highly reactive substrates in catalytic, chemoselective polyol transformations.
Copper-catalyzed enantioselective allylic cross-coupling with alkylboranes
Hojoh, Kentaro,Shido, Yoshinori,Nagao, Kazunori,Mori, Seiji,Ohmiya, Hirohisa,Sawamura, Masaya
, p. 6519 - 6533 (2015/08/18)
Abstract We have presented full details of our work on alkylboranes, which we have introduced as new reagents for copper-catalyzed SN2′-type enantioselective allylic substitutions. The copper catalysis delivered enantioenriched chiral products containing tertiary or quaternary carbon stereogenic centers branched with functionalized sp3-alkyl groups. The wide availability of alkylboranes via the established alkene hydroboration reaction is an attractive feature of these transformations. Various functional groups are tolerated in the substrates. A reaction pathway involving addition-elimination of a neutral alkylcopper(I) species with the allyl chloride substrate is proposed.
The synthesis of chiral amino diol tridentate ligands and their enantioselective induction during the addition of diethylzinc to aldehydes
Zhang, An-Lin,Yang, Li-Wen,Yang, Nian-Fa,Liu, Yan-Ling
, p. 289 - 297 (2014/04/03)
A series of C2-symmetric chiral amino diol tridentate ligands 3a-g were prepared from achiral bulky organolithiums, achiral bulky primary amines, and optically active epichlorohydrin (ECH). The prepared C 2-symmetric chiral amino diol tridentate ligands were capable of inducing enantioselectivity in the model reaction of aromatic and aliphatic aldehydes with diethylzinc with an ee of up to 96%. The enantioselectivity can be modulated by adjusting the steric hindrance of the achiral reagents employed in the synthesis of the chiral ligand. The configuration of the addition product depended on the configuration of the amino diol ligands, which can be simply controlled as desired by using the ECH with the desired configuration during the preparation of the ligand.
Enantioselectivity switch controlled by N,N′-di- or N,N,N′,N′-tetra-substituted chiral thiophosphorodiamide ligands, structural relatives of thioureas, in catalytic additions of diethylzinc to aldehydes
Yue, Huifeng,Huang, Huayin,Bian, Guangling,Zong, Hua,Li, Fangling,Song, Ling
, p. 170 - 180 (2014/02/14)
We have developed a series of new chiral thiophosphorodiamide ligands derived from (1R,2R)-(+)-1,2-diphenylethylenediamine, which are the structural relatives of thioureas. An investigation into their catalytic properties in asymmetric additions of diethylzinc to aldehydes has shown that N,N,N′,N′-tetra-substituted chiral thiophosphorodiamides can give (R)-secondary alcohols with up to 98% yield and 98% ee, while N,N′-di-substituted chiral thiophosphorodiamides give (S)-secondary alcohols with up to 99% yield and 97% ee values. The enantioselectivity switch is highly efficient with a broad substrate scope. We have also proposed hypothetical reaction pathways, which result in an enantioselectivity switch.
Vasicine as tridentate ligand for enantioselective addition of diethylzinc to aldehydes
Aga, Mushtaq A.,Kumar, Brijesh,Rouf, Abdul,Shah, Bhahwal A.,Taneja, Subhash C.
supporting information, p. 2639 - 2641 (2014/05/06)
The first report of natural l-vasicine as tridentate chiral ligand for the enantioselective addition of diethylzinc to a variety of aliphatic and aromatic aldehydes is described. The ligand generates R-isomer of the secondary alcohols upto 98% ee. The qui
A palladium nanoparticle-nanomicelle combination for the stereo-selective semihydrogenation of alkynes in water at room temperature
Slack, Eric D.,Gabriel, Christopher M.,Lipshutz, Bruce H.
, p. 14051 - 14054 (2015/02/19)
The addition of NaBH4 to Pd(OAc) 2 in water containing nanomicelles leads to the generation of H2 and Pd nanoparticles. Subsequent reduction of disubstituted alkynes affords Z-alkenes in high yields. These reactions are general, take place in water at ambient temperatures, and offer recycling of the aqueous reaction mixture along with low overall E Factors.
Chiral surfactant-type catalyst for asymmetric reduction of aliphatic ketones in water
Li, Jiahong,Tang, Yuanfu,Wang, Qiwei,Li, Xuefeng,Cun, Linfeng,Zhang, Xiaomei,Zhu, Jin,Li, Liangchun,Deng, Jingen
supporting information, p. 18522 - 18525 (2013/01/15)
A novel chiral surfactant-type catalyst is developed. Micelles formed in water by association of the catalysts themselves, and this was confirmed by TEM analyses. Asymmetric transfer hydrogenation of aliphatic ketones catalyzed by the chiral metallomicellar catalyst gave good to excellent conversions and remarkable stereoselectivities (up to 95% ee). Synergistic effects between the metal-catalyzed center and the hydrophobic microenvironment of the core in the metallomicelle led to high enantioselectivities.
Copper-catalyzed enantioselective allylic substitution with alkylboranes
Shido, Yoshinori,Yoshida, Mika,Tanabe, Masahito,Ohmiya, Hirohisa,Sawamura, Masaya
supporting information, p. 18573 - 18576 (2013/01/15)
The first catalytic enantioselective allylic substitution reaction with alkylboron compounds has been achieved. The reaction between alkyl-9-BBN reagents and primary allylic chlorides proceeded with excellent γ-selectivities and high enantioselectivities under catalysis of a Cu(I)-DTBM-SEGPHOS system. The protocol produces terminal alkenes with an allylic stereogenic center branched with functionalized sp3-alkyl groups. The reaction with a γ-silicon-substituted allyl chloride affords an efficient strategy for the enantioselective synthesis of functionalized α-stereogenic chiral allylsilanes.
(1R,5R)-1-(1-dimethylaminoethyl)-2-isopropylidene-5-methylcyclohexanol as a chiral ligand in the enantioselective addition of diethylzinc to aldehydes
Yadav, Ashok K.,Kumar, Manoj,Yadav, Tripti,Jain, Renuka
scheme or table, p. 712 - 714 (2010/06/13)
An efficient chiral ligand, (1R,5R)-1-(1-dimethylaminoethyl)-2- isopropylidene-5-methylcyclohexanol, has been developed for the enantioselective addition of diethylzinc to some prochiral aldehydes to afford S-alcohols. The overall conversion rate was 80-98% with excellent enantiomeric excess (79-98%). Georg Thieme Verlag Stuttgart ? New York.
Tin-free giese reaction and the related radical carbonylation using Alkyl iodides and cyanoborohydrides
Ryu, Ilhyong,Uehara, Shohei,Hirao, Hidefumi,Fukuyama, Takahide
body text, p. 1005 - 1008 (2009/04/07)
Tin-free Giese reaction and the related radical carbonylation process proceeded efficiently in the presence of sodium cyanoborohydride and tetrabutylammonium cyanoborohydride. The reaction took place chemoselectively at the carbon-iodine bond but not at the carbon-bromine and carbon-chlorine bonds. The iodine atom transfer followed by hydride reduction of the resulting carbon-iodine bond is proposed as a possible mechanism.
