Ti-direct, powerful, stereoselective aldol-type additions of esters and thioesters to carbonyl compounds: application to the synthesis and evaluation of lactone analogs of jasmone perfumes
thiophenyl esters or thioaryl esters with aldehydes and ketones was performed (total 46 examples). The present method is advantageous from atom-economical and cost-effective viewpoints; good to excellent yields, moderate to good syn-selectivity, substrate variations, reagent availability, and simple procedures. Utilizing the present reaction as the key step, an efficient short synthesis of three lactone
[Structure: see text] A powerful Ti-crossed Claisen condensation between ketene silyl acetals (KSAs) and acid chlorides was successfully performed to give alpha-monoalkylated esters and thermodynamically unfavorable (less accessible) alpha,alpha-dialkylated beta-keto esters in good yield (46 examples; 41-98% yield). A closely related reaction between ketene silyl thioacetals (KSTAs) and acid chlorides also
Stereospecific Synthesis of Fluoroalkenes by Silver-Mediated Fluorination of Functionalized Alkenylstannanes
作者:Heiko Sommer、Alois Fürstner
DOI:10.1002/chem.201605444
日期:2017.1.12
sorts. Key to success is the use of F‐TEDA‐PF6 in combination with non‐hygroscopic and bench‐stable silver phosphinate (AgOP(O)Ph2) that acts as an essentially neutral, non‐nucleophilic promotor and effective tin‐scavenger at the same time. This new method opens many opportunities for late‐stage fluorination of elaborate compounds far beyond the scope of the literature procedures, as witnessed by the preparation
The Hydroboration of 1-Alkylthio-l-alkynes, and Its Application to the Syntheses of<i>S</i>-Alkyl Alkanethioates and (<i>Z</i>)-1-Alkylthio-1-alkenes
作者:Masayuki Hoshi、Yuzuru Masuda、Akira Arase
DOI:10.1246/bcsj.63.447
日期:1990.2
Hydroboration of 1-alkylthio-1-alkynes with dicyclohexylborane or bis(1,2-dimethylpropyl)borane proceeded smoothly, adding most of the dialkylboryl group to the α-position of the triple bond. The resulting alkenylboranes afforded either S-alkyl alkanethioates on a controlled oxidation with alkaline hydrogen peroxide in the presence of N,N,N′,N′-etramethylethylenediamine or (Z)-1-alkylthio-1-alkenes on a basic protonolysis, successive treatments with methyllithium, copper(I) iodide and water in the presence of hexamethylphosphoric triamide.
Synthesis of S-alkyl alkanethioates via 1-iodoalk-1-enyldialkylboranes
作者:Masayuki Hoshi、Yuzuru Masuda、Akira Arase
DOI:10.1039/c39850000714
日期:——
S-Alkylalkanethioates were formed in high yields by successive reactions of 1-iodoalk-1-enylbis(1,2-dimethylpropyl)boranes with alkylthiomagnesium bromides and alkaline hydrogen peroxide.