3-alcoxy-allenyllithium reagents as β-acyl vinyl anion equivalents. A new synthesis of pyrenophorin.
作者:Fadila Derguini、Gérard Linstrumelle
DOI:10.1016/s0040-4039(01)81680-4
日期:1984.1
3-alcoxy-allenyllithium reagents with electrophiles led to (Z) or (E) keto compounds 3 or 4 after mild acid hydrolysis. Carboxylation led to the 4-oxo-2-alkenoate unit. This reaction was applied to a short synthesis of the macrolide antibiotic, pyrenophorin.
Reactivity of the 1-t.butylthio-3-methoxy-1-alkenes towards metalating agents, II. Allylic deprotonation of the E-isomers and of the Z-propenyl derivative.
作者:O. Ruel、C.Bibang Bi Ekogha、S.A. Julia
DOI:10.1016/s0040-4039(00)94018-8
日期:1983.1
Deprotonation of the title compounds with a lithiating agent and subsequent alkylation furnish the 1-substituted products . The 1-t.butylthio-3-methoxy-1-lithio-1-alkenes become newequivalents of the hypothetical anions I.
Allylic alcohols of unexpected configuration by oxazaborolidine-catalysed reduction of α,β-unsaturated ketones. An explanation based on MO calculations
While the reduction of most alpha,beta-unsaturated ketones with BH3:SMe(2) in the presence of (R)B-methyl-4,5,5-triphenyl-1,3,2-oxazaborolidine [(R)-2] affords allylic alcohols of the S configuration, that of alpha,beta-unsaturated ketones branched at both the alpha and alpha' positions gives alcohols of the R configuration. Theoretical calculations on complexes of representative enones with BH3 (6-31G*) or with BH3:(R)-2 (AMI) may account for the apparent changes in the steric requirements on either side of the CO group.
RUEL, O.;EKOGHA, C. BIBANG, BI;JULIA, S. A., TETRAHEDRON LETT., 1983, 24, N 44, 4829-4832