Chiroptical Properties and Absolute Configuration of Chiral, Open Chain Di- and Tri-substituted Allenes: a Polarizability Approach

A second order treatment of the optical activity of chiral diand tri-substituted open chain allenes, by means of the polarizability model of DeVoe, makes it possible to establish a simple relationship between optical rotatory power and absolute configuration of these compounds

Stereoselective Transformations Starting with Chiral (Alkoxy)methyl-Substituted Organosilicon Compounds

The following short review summarizes the results we achieved with the investigation of chiral silicon groups as auxiliaries for the enantioselective synthesis. (Alkoxy)methyl-substituted silicon compounds with 'Si-centered chirality', which were prepared in optically active form by application of a bioreduction, have been efficiently used as starting materials for a number of stereoselective reactions. Acylsilanes of this type upon treatment with organometallic reagents gave rise to 1,2-addition products with high degrees of stereoselectivities. The respective α-hydroxysilanes could be stereospecifically desilylated to chiral secondary alcohols, or, depending on the substitution pattern, further used as starting compounds for stereocontrolled oxidation, Cope- or Claisen-type rearrangement reactions. Chiral α-metallated vinylsilanes were converted to α-silyl-substituted allylic alcohols and to α-silyl-substituted α,β-unsaturated ketones. The prior led to chiral allenes in a Peterson-type reaction – however, without stereoselectivity – the latter delivered stereoselectively β-chiral silicon-free ketones upon stereocontrolled conjugate cuprate addition followed by removal of the silicon auxiliary

Rhodium catalysed intermolecular chelation controlled hydroacylation

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Exploration of the in situ generation and use of trialkyltin hydrides and studies toward the syntheses of sea lamprey pheromones

Thesis (Ph. D.)--Michigan State University. Department of Chemistry, 2007Includes bibliographical references (pages 241-254

Selenium-mediated allenylation and allylation reactions of N- and O-nucleophiles

Selenium-pi-acid catalysis has been gaining popularity in functionalization reactions of unactivated olefins due to their lower cost and toxicity compared to traditional transition metal catalysts. Some examples of Se-mediated reactions include amination reactions, allylic esterification reactions, and acyloxylation reactions using simple, non-activated olefins. In the first project of this thesis, selenium-pi-acid-catalysis has been used for the functionalization of simple, non-functionalized alkynes. A number of aminoallenes were synthesized from commercially available alkynes using (o-anisyl)2Ph2 as catalyst and NFSI as the source of nucleophile and terminal oxidant. The key feature of this method is that the incorporation of the desired nucleophile and the adjustment of the oxidation state in the final product takes place in a single-step operation. In the second project of this thesis, a new method for the formation of a C-O bond has been described. Allylic phenyl selenides were found to undergo nucleophilic substitution at the selenide with a carboxylic acid nucleophile under irradiation with light of a suitable wavelength. The oxidative activation of the selenide for the substitution reaction is hypothesized to be due to the formation of hydrogen bond networks with the solvent HFIP. The key feature of this method is the chemoselectivity of the reaction and that no extraneous reagent is required for the oxidative activation of the selenium-moiety

Archiv für die Geschichte Liv-, Est- und Curlands Neue Folge Bd.VIII

http://tartu.ester.ee/record=b1318707~S1*es