Synthesis of (−)-Vulcanolide by Enantioselective Protonation
摘要:
Two efficient enantioselective syntheses of the more active (S,S)enantiomer of the powerful musk odorant Vulcanolide are described. In both syntheses, the key step is an enantioselective protonation of a ketone enolate. A third enantioselective protonation, of a thiol ester enolate, was applied for the determination of the absolute configuration of Vulcanolide by comparison with a known compound.
Stereochimie de quelques reactions entre aldehydes et reactifs de Grignard satures et allyliques
作者:H. Felkin、Y. Gault、G. Roussi
DOI:10.1016/s0040-4020(01)92953-9
日期:1970.1
γ-dimethylallyl magnesium bromides) and secondary alkyl [s-butyl magnesium bromide and (1,2-dimethylpropyl) magnesium chloride] Grignardreagents to form pairs of diastereoisomeric alcohols R′—CHMeCHOH—R (R′ = CH2CH, CH2CMe, Et and iPr, respectively). The reactions involving the secondary alkylGrignardreagents are not stereoselective; those involving the allylic Grignardreagents show some stereoselectivity
A convenient and diastereoselective route to homoallyl alcohols: Addition of (z)- or (e)-alkenyl-dimethoxyboranes to aldehydes
作者:Katsuramaru Fujitta、Manfred Schloser
DOI:10.1002/hlca.19820650415
日期:1982.6.16
(Z)-2-Butenyl-dimethoxyborane adds smoothly to propanal and benzaldehyde to afford the homoallyl alcohols (R*,R*)-1 and (R*,R*)-2, In contrast (E)-2-butenyl-dimethoxyborane leads to adducts having the (R*,S*)-configuration. Dimethoxy-(Z)-2-pentenylborane, dimethoxy-(Z)-(2-methyl-2-butenyl)borane and (2Z,4E)-or (2E,4Z)hexadienyl-dimethoxyborane, treated with propanal, give (R*,R*)-3, (R*,R*)-4, (E)
Synthesis of unsaturated sulfides via cross-coupling of Grignard reagents with allylic electrophiles with simultaneous incorporation of sulfur into the metal-carbon bond
作者:U. M. Dzhemilev、E. V. Gribanova、A. G. Ibragimov