RESUMEN
The enantioselective kinetic resolution of ß-unfunctionalized primary alcohols with benzoyl chloride was carried out in the presence of a catalytic amount of a novel chiral 1,2-diamine derived from (S)-proline. Several valuable chiral 2-substituted propan-1-ols were obtained with good enantioselectivities. Density functional theory calculations revealed that the noncovalent interaction, such as CH-π interaction, is crucial for the enantioselectivity of the resolution. This study was conducted through an interplay between experiment and computation.
Asunto(s)
Alcoholes , Diaminas , Catálisis , Cinética , EstereoisomerismoRESUMEN
Maleimides are often used as electrophiles in conventional reactions; however, their application as nucleophiles is limited to only a few reactions, and reactions utilizing α-aminomaleimides as asymmetric Michael donors have not been reported to date. Thus, in this work, asymmetric Michael addition of α-aminomaleimides as Michael donors to ß-nitrostyrenes was conducted for the first time using an organocatalyst derived from a Cinchona alkaloid. Density functional theory investigations were crucial to improve the enantioselectivity of the adduct.
Asunto(s)
Alcaloides de Cinchona/química , Maleimidas/química , Estirenos/química , Reacción de Cicloadición , Estructura MolecularRESUMEN
[reaction: see text] Iron(III) chloride-catalyzed effective allylation reactions of acetals with allyltrimethylsilane proceeded smoothly in high to excellent yields. In addition, this method could be applied to the one-pot synthesis of homoallyl benzyl ethers by a combination of dibenzyl acetalization of aldehydes and consecutive allylation of dibenzyl acetals.
RESUMEN
[reaction: see text] In the presence of MS 4A in DMSO, cyanobenzoylation of various aldehydes with benzoyl cyanide proceeded very smoothly to give the corresponding cyanohydrin benzoates in high to excellent yields without an acid or a base. On the other hand, reaction of aldehydes with BzCN in DMSO-H(2)O also occurred readily to afford the corresponding free cyanohydrins exclusively.
RESUMEN
We performed PMC-CPT-11 therapy (modified pharmacokinetic modulating chemotherapy plus irinotecan, or modified PMC) in a case of sigmoid colon cancer with local invasion and multiple hepatic metastases. This regimen combined PMC therapy which includes Hartmann's operation, simple hysterectomy and postoperative 5-fluorouracil (5-FU), with intravenous irinotecan, or CPT-11. The multiple hepatic metastatic lesions disappeared after surgery and no local recurrence has been found since. These results indicate that PMC-CPT-11 (modified PMC) therapy could be an effective regimen for cases of progressive colon cancer in the future.