Copper(I)-Catalyzed Enantioselective 1,6-Borylation of α,β,γ,δ-Unsaturated Phosphonates
作者:Hyesu Lee、Jaesook Yun
DOI:10.1021/acs.orglett.8b03532
日期:2018.12.21
Copper(I)-catalyzed asymmetric 1,6-borylation of 1,3-dienylphosphonates was achieved using (S,S)-Ph-BPE as a chiral ligand. Regio-, stereo-, and enantioselective borylation successfully proceeded to afford phosphonate-containing allylboronates, with high enantioselectivity up to 97% ee. Further applications of the resulting products generated a valuable phosphonate analogue of γ-butyrolactone.
of silyl substituents in diphenylprolinolsilylether catalysts was investigated. Mechanistically, reactionscatalyzed by diphenylprolinolsilylether can be categorized into three types: two that involve an iminium ion intermediate, such as for the Michael‐type reaction (type A) and the cycloaddition reaction (type B), and one that proceeds via an enamine intermediate (type C). In the Michael‐type
Total Synthesis of the Ramoplanin A2 and Ramoplanose Aglycon
作者:Wanlong Jiang、Jutta Wanner、Richard J. Lee、Pierre-Yves Bounaud、Dale L. Boger
DOI:10.1021/ja0212314
日期:2003.2.19
stage racemization of carboxylate-activated phenylglycine-derived residues, and to enlist beta-sheet preorganization of an acyclic macrocyclization substrate for 49-membered ring closure. As such, macrocyclization at the chosen Phe(9)-D-Orn(10) site may benefit from both beta-sheet preorganization as well as closure at a D-amine terminus. Deliberate late stage incorporation of the subunit bearing the
Organocatalytic Michael Addition of Nitro Esters to α,β-Unsaturated Aldehydes: Towards the Enantioselective Synthesis of<i>trans</i>-3-Substituted Proline Derivatives
作者:Man-Yi Han、Yong Zhang、Huai-Zhen Wang、Wan-Kai An、Bao-Chun Ma、Yuan Zhang、Wei Wang
DOI:10.1002/adsc.201200538
日期:2012.10.8
five-step strategy has been developed for the enantioselective synthesis of trans-3-substituted proline derivatives with high diasteroselectivity (dr>20:1) and enantioselectivity (up to 97% ee). The key step is the asymmetric organocatalyticMichaeladdition of nitro esters to α,β-unsaturatedaldehydes, which affords the chiral Michael adducts in high yields (up to 96%) and excellent enantioselectivity
Metal-Free Catalytic Enantioselective C–B Bond Formation: (Pinacolato)boron Conjugate Additions to α,β-Unsaturated Ketones, Esters, Weinreb Amides, and Aldehydes Promoted by Chiral N-Heterocyclic Carbenes
作者:Hao Wu、Suttipol Radomkit、Jeannette M. O’Brien、Amir H. Hoveyda
DOI:10.1021/ja302929d
日期:2012.5.16
0]undec-7-ene (dbu). In addition to the commercially available bis(pinacolato)diboron [B(2)(pin)(2)], and in contrast to reactions with the less sterically demanding achiral NHCs, the presence of MeOH is required for high efficiency. Acyclic and cyclic α,β-unsaturated ketones, as well as acyclic esters, Weinreb amides, and aldehydes, can serve as suitable substrates; the desired β-boryl carbonyls are