Asymmetric synthesis using a new chiral β-functionalized allylboronate derived from endo-2-phenyl-exo-2,3-bornanediol: Preparation and reactions with aldehydes
The allylboron reagent 4 prepared from endo-2-phenyl-exo-2,3-bornanediol reacts with achiral aldehydes to give homoallylic alcohols in good yields and high enantioselectivity (70–85% ee). This new reagent also exhibits good levels of matched and mismatched diastereoselection in reaction with chiralaldehydes. A mechanism is proposed to explained the high regio and stereoselectivity of this carboalkoxyallylboration
Tailored α-methylene-γ-butyrolactones and their effects on growth suppression in pancreatic carcinoma cells
作者:P. Veeraraghavan Ramachandran、Debarshi Pratihar、Hari Narayanan G. Nair、Matthew Walters、Sadie Smith、Michele T. Yip-Schneider、Huangbing Wu、C. Max Schmidt
DOI:10.1016/j.bmcl.2010.09.022
日期:2010.11
A selected series of racemic alpha-methylene-gamma-butyrolactones (AMGBL) were synthesized via allylboration and screened against three human pancreatic cancer cell lines (Panc-1, MIA PaCa-2, and BxPC-3). This systematic study established a discernible relationship between the substitution pattern of AMGBL and their anti-proliferative activity. beta,gamma-diaryl-AMGBLs, particularly those with a trans-relationship exhibited higher potency than parthenolide and LC-1 against all three cell lines. (C) 2010 Elsevier Ltd. All rights reserved.
Enantioselective addition of β-functionalized allylboronates to aldehydes and aldimines. Stereocontrolled synthesis of α-methylene-γ-lactones and lactams
We report results regarding the development of condensations of chiral β-alkoxycarbonylallylboronates on aldehydes and imines. These allylboronates add in a highly enantioselective and diastereospecific manner to afford biologically and synthetically useful chiral α-methylene-γ-butyrolactones and lactams. The nature of the electrophile (aldehyde vs imine) is shown to have a dramatic influence on the