Stereocontrolled preparation of 1,2-diol with quaternary chiral center
摘要:
Development of an enantio- and stereoselective construction of 1,2-diols including a quaternary chiral center was achieved by a titanium-mediated aldol reaction of lactates bearing chiral oxazolidine-2-ones. anti-Aldol and syn-aldol were selectively obtained by the choice of a benzyl and TBS protecting group, respectively. Plausible transition states are also shown based on the stereochemistry of the enolate anion. (C) 2002 Elsevier Science Ltd. All rights reserved.
Stereocontrolled preparation of 1,2-diol with quaternary chiral center
摘要:
Development of an enantio- and stereoselective construction of 1,2-diols including a quaternary chiral center was achieved by a titanium-mediated aldol reaction of lactates bearing chiral oxazolidine-2-ones. anti-Aldol and syn-aldol were selectively obtained by the choice of a benzyl and TBS protecting group, respectively. Plausible transition states are also shown based on the stereochemistry of the enolate anion. (C) 2002 Elsevier Science Ltd. All rights reserved.
The first totalsynthesis of incednam (1), the aglycon of antibiotic incednine (2), is described. Incednine has been reported to exhibit significant inhibitory activity against the antiapoptotic oncoproteins Bcl-2 and Bcl-xL. The synthesis of 1 commenced with the preparation of the C1−C13 subunit 3 and the C14−C23 subunit 4. The construction of the novel 24-membered macrocycle was achieved by the application