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
BOLDRINI, GIAN PAOLO;LODI, LUISA;TAGLIAVINI, EMILIO;TARASCO, CARMINE;TROM+, J. ORG. CHEM., 52,(1987) N 24, 5447-5452
作者:BOLDRINI, GIAN PAOLO、LODI, LUISA、TAGLIAVINI, EMILIO、TARASCO, CARMINE、TROM+
DOI:——
日期:——
Synthesis of optically active α-methylene γ-lactones through lipase-catalyzed kinetic resolution
作者:Waldemar Adam、Peter Groer、Chantu R Saha-Möller
DOI:10.1016/s0957-4166(00)00174-9
日期:2000.6
The lipase-catalyzedkineticresolution of the γ-hydroxy esters 1a,b and their subsequent acid-mediated cyclization afford the opticallyactive α-methylene γ-lactones 2a,b in high yields (71–89%) and in up to 95% enantiomeric excess. The direct enzymatic lactonization of the racemic γ-hydroxy esters 1a,b to the lactones 2a,b represents a less satisfactory alternative, since poor enantioselectivies