Enantioselective reduction of α,β-enones using an oxazaborolidine catalyst generated in situ from a chiral lactam alcohol
作者:Yasuhiro Kawanami、Yudai Mikami、Kazuya Kiguchi、Yuki Harauchi、Ryo C. Yanagita
DOI:10.1016/j.tetasy.2011.10.018
日期:2011.11
The oxazaborolidine catalyst prepared in situ from the chiral lactam alcohol 3 and 4-iodophenoxyborane was found to catalyze the enantioselective reduction of α,β-enones at −40 °C with a high level of enantioselectivity of up to 90% ee.
No base required: The first copper‐catalyzed asymmetric hydrosilylation of carbonyl compounds by using monodentate binaphthophosphepine ligands is presented. After optimization of the reaction parameters, high yields and enantioselectivities (up to 96 % ee) for a broad range of aryl alkyl, cyclic, heterocyclic, and aliphatic ketones are achieved without a base.
[EN] CHIRAL METAL COMPLEX COMPOUNDS<br/>[FR] COMPOSÉS COMPLEXES MÉTALLIQUES CHIRAUX
申请人:HOFFMANN LA ROCHE
公开号:WO2018189060A1
公开(公告)日:2018-10-18
The invention comprises novel chiral metal complex compounds of the formula (I) wherein M, PR2, R3 and R4 are outlined in the description, its stereoisomers, in the form as a neutral complex or a complex cation with a suitable counter ion. The chiral metal complex compounds can be used in asymmetric reactions, particularly in asymmetric reductions of ketones, imines or oximes.
Asymmetric Hydrosilylation of Ketones Using<b><i>Trans</i></b>-Chelating Chiral Peralkylbisphosphine Ligands Bearing Primary Alkyl Substituents on Phosphorus Atoms
作者:Ryoichi Kuwano、Masaya Sawamura、Junya Shirai、Masatoshi Takahashi、Yoshihiko Ito
DOI:10.1246/bcsj.73.485
日期:2000.2
Asymmetric hydrosilylation of simple ketones with diphenylsilane proceeded at -40 °C in the presence of a rhodium complex (0.001—0.01 molar amount) coordinated with a trans-chelating chiral bisphosphine ligand bearing linear alkyl substituents on the phosphorus atoms, (R,R)-(S,S)-Et-, Pr-, or BuTRAP, giving the corresponding optically active (S)-secondary alcohols with up to 97% ee. The asymmetric
简单酮与二苯基硅烷的不对称氢化硅烷化在 -40 °C 下在铑配合物(0.001-0.01 摩尔量)存在下进行,该配合物与在磷原子上带有线性烷基取代基的反式螯合手性双膦配体(R,R) -(S,S)-Et-、Pr- 或 BuTRAP,得到相应的光学活性 (S)-仲醇,其 ee 高达 97%。使用具有更大 P 取代基的 TRAP 配体的不对称氢化硅烷化导致低得多的对映选择性。EtTRAP-铑催化剂对于具有铑原子配位位点的酮酯的不对称氢化硅烷化也有效(高达 98% ee)。通过使用 2.5 摩尔二苯基硅烷的不对称还原,从相应的二酮中获得了高达 99% ee 的旋光对称二醇。
Manganese Catalyzed Asymmetric Transfer Hydrogenation of Ketones Using Chiral Oxamide Ligands
The asymmetric transferhydrogenation of ketones using isopropyl alcohol (IPA) as hydrogen donor in the presence of novel manganese catalysts is explored. The selective and active systems are easily generated in situ from [MnBr(CO)5] and inexpensive C 2-symmeric bisoxalamide ligands. Under the optimized reaction conditions, the Mn-derived catalyst gave higher enantioselectivity compared with the related
探索了在新型锰催化剂存在下使用异丙醇 (IPA) 作为氢供体的酮的不对称转移氢化。选择性和活性系统很容易由 [MnBr(CO)5] 和廉价的 C 2 对称双草酰胺配体原位生成。在优化的反应条件下,Mn 衍生的催化剂与相关的钌催化剂相比具有更高的对映选择性。