Bis-Chlorodibutyltin Oxide as a New Reagent for a Mild, Versatile and Regioselective Ring-Opening of Epoxides
作者:Claudio J. Salomon
DOI:10.1055/s-2001-9727
日期:——
A convenient and efficient procedure for the ring-opening of epoxides by means of alcohols and bis-chlorodibutyltin oxide is described. The cleavage of the oxiranes is found to proceed regioselectively under mild reaction conditions. Thus, several haloalkanols, useful intermediates toward biological active molecules, are easily obtained in very good yields.
Cooperative Brønsted Acid-Type Organocatalysis: Alcoholysis of Styrene Oxides
作者:Torsten Weil、Mike Kotke、Christian M. Kleiner、Peter R. Schreiner
DOI:10.1021/ol800149y
日期:2008.4.1
We present a mild and efficient method for the completely regioselective alcoholysis of styrene oxides utilizing a cooperative Bronsted acid-type organocatalytic system comprised of mandelic acid (1 mol %) and N,N'-bis-[3,5-bis-(trifluoromethyl)phenyl]-thiourea (1 mol %). Various styrene oxides are readily transformed into their corresponding beta-alkoxy alcohols in good to excellent yields at full conversion. Simple aliphatic and sterically demanding, as well as unsaturated and acid-sensitive alcohols can be employed.
Cross‐linked poly(
<i>N</i>
‐vinylpyrrolidone)‐titanium tetrachloride complex: A novel stable solid TiCl
<sub>4</sub>
equivalent as a recyclable polymeric Lewis acid catalyst for regioselective ring‐opening alcoholysis of epoxides
作者:Ali Rahmatpour、Seyed Mehrzad Sajjadinezhad
DOI:10.1002/aoc.6385
日期:2021.11
thermogravimetric analysis (TGA) techniques. Moreover, the catalyst is very stable, easily separated, and reused at least five times without significant loss of activity. In terms of scope, yields, the amount of catalyst used, and reaction time, the PNVP-TiCl4 complexcatalyst is an improvement over previously reported heterogeneous catalysts for ring opening of epoxides methods. Further, the experimental outcome
Synergistic Peptide and Gold Catalysis: Enantioselective Addition of Branched Aldehydes to Allenamides
作者:Leo D. M. Nicholls、Helma Wennemers
DOI:10.1002/chem.202103197
日期:2021.12.15
A synergistic combination of a tripeptide and a gold complex catalyzes the enantioselectiveaddition between branchedaldehydes and allenamides to furnish synthetically versatile γ,δ-enamide aldehydes with a fully substituted stereogenic center. Mechanistic studies offered key insights into the role of the peptide and acid/base additives.