as Lewis base catalysts are reported. Lewis bases containing the 3,5-bis(trifluoromethyl)phenyl group were found to be significantly more enantioselective for a wider range of substrates than those bearing aromatic residues that are not strongly electron-deficient in the allylation of aldehydes with allyltrichlorosilane. Also, optically pure 3,3′-dibromo-1,1′-biisoquinoline N,N′-dioxide that has not
of C10-BridgePHOS oxides possessing different substituted groups on the diphenyl phosphine system were synthesized and tested as organocatalysts in the allylation of aldehydes with allyltrichlorosilane, providing chiral homoallylic alcohols. These types of organocatalysts showed high catalytic activity and only 2 mol% catalyst loading was required to induce short reaction times. Under optimal reaction
Asymmetric Allylation of Aldehydes Catalyzed by Simple Dual Small Organic Molecules: L-Proline and L-Prolinol
作者:Guo-hong Chen、Ling-yan Liu、Xiao-ning Wei、Wei-xing Chang、Jing Li
DOI:10.1246/cl.2010.1013
日期:2010.9.5
A novel and simple methodology for the asymmetric allylation of aldehydes was reported. Double small organic molecules such as l-proline and l-prolinol were first employed for providing a chiral environment so as to afford chiral homoallylic alcohols in high yields and moderate enantioselectivities in our protocol.
A chiral oxazoline for catalytic enantioselective Nozaki-Hiyama-Kishi allylation and vinylation of aldehydes
作者:Sharad V. Kumbhar、Chinpiao Chen
DOI:10.1016/j.catcom.2020.106166
日期:2021.1
Asymmetric allylation and vinylation of aldehydes with allyl halides and vinyl halides have been achieved using the chromium(II)-oxazoline catalyst. The catalyst promotes the highly efficient enantioselective Nozaki–Hiyama-Kishi (NHK) allylation of aldehydes usingallyl bromide, producing the corresponding homoallylic alcohols in good yields (up to 84%) and a high level of enantioselectivity (up to
Asymmetric allylboration of aldehydes with allylboronic acid pinacol ester catalyzed by chiral hydroxyl carboxylic acid is described. This reaction provides synthetically useful homoallyl alcohols in high yield with good to high enantioselectivity. The present catalytic protocol was also examined in asymmetric allenylboration of aldehydes at elevated temperature to afford chiral homopropargyl alcohols with