Asymmetric Aldol Additions: Use of Titanium Tetrachloride and (−)-Sparteine for the Soft Enolization of <i>N-</i>Acyl Oxazolidinones, Oxazolidinethiones, and Thiazolidinethiones
作者:Michael T. Crimmins、Bryan W. King、Elie A. Tabet、Kleem Chaudhary
DOI:10.1021/jo001387r
日期:2001.2.1
N-methyl-2-pyrrolidinone, selectivities of 97:3 to > 99:1 were obtained for the Evans syn aldol products using N-propionyl oxazolidinones, oxazolidinethiones, and thiazolidinethiones. The non-Evans syn aldol adducts are available with the oxazolidinethione and thiazolidinethiones by altering the Lewisacid/aminebase ratios. The change in facial selectivity in the aldoladditions is proposed to be a result of
Direct and Enantioselective Aldol Reactions Catalyzed by Chiral Nickel(II) Complexes
作者:Stuart C. D. Kennington、Saul F. Teloxa、Miguel Mellado‐Hidalgo、Oriol Galeote、Sabrina Puddu、Marina Bellido、Pedro Romea、Fèlix Urpí、Gabriel Aullón、Mercè Font‐Bardia
DOI:10.1002/anie.202104352
日期:2021.7.5
A direct and asymmetric aldol reaction of N-acyl thiazinanethiones with aromatic aldehydes catalyzed by chiral nickel(II) complexes is reported. The reaction gives the corresponding O-TIPS-protected anti-aldol adducts in high yields and with remarkable stereocontrol and atom economy. Furthermore, the straightforward removal of the achiral scaffold provides enantiomerically pure intermediates of synthetic
报道了由手性镍 (II) 配合物催化的N-酰基噻嗪烷硫酮与芳香醛的直接和不对称醛醇反应。该反应以高产率和显着的立体控制和原子经济性得到相应的O -TIPS 保护的抗醛醇加合物。此外,非手性支架的直接去除提供了合成感兴趣的对映异构纯中间体,其中涉及抗-α-氨基-β-羟基和α,β-二羟基羧酸衍生物的前体。理论计算解释了观察到的高立体控制。
Simple and highly diastereoselective synthesis of a 1β-methylcarbapenem key intermediate involving divalent tin enolates
作者:Robert Déziel、Denis Favreau
DOI:10.1016/s0040-4039(00)85301-0
日期:——
A simple and diastereoselective synthesis of 1β-methylcarbapenemkeyintermediate has been accomplished via a novel CC bond formation at the C-4 position of 4-acetoxyazetidinone involving divalent tin enolates of 3-propanoyl thiazolidine and oxazolidine-2-thiones derivatives.
Direct, Stereodivergent, and Catalytic Michael Additions of Thioimides to α,β‐Unsaturated Aldehydes – Total Synthesis of Tapentadol
作者:Oriol Galeote、Stuart C. D. Kennington、Gabriela Benedito、Lena Fraedrich、Evan Davies‐Howe、Anna M. Costa、Pedro Romea、Fèlix Urpí、Gabriel Aullón、Mercè Font‐Bardia、Cristina Puigjaner
DOI:10.1002/anie.202319308
日期:2024.3.18
regioselective and stereodivergent Michael additions of thioimides to α,β-unsaturated aldehydes catalyzed by chiral nickel complexes give any of the potential syn and anti diastereomers, at will, with good to high yields. The resultant adducts can be easily transformed into a wide array of enantiomericallypure intermediates ready to participate in the asymmetricsynthesis of biologically active compounds.