Search for dissertations about: "Lewis acid"

Showing result 21 - 25 of 69 swedish dissertations containing the words Lewis acid.

  2. 21. Lewis acid promoted endocyclic cleavage of glycosides and related acetals

    Author : Roger Olsson; Centrum för analys och syntes; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; halichomycin; allylation; carbene; hydrogen bond; organozinc; organotitanium; furanosides; organoaluminium; pyranosides; glycosides; stereoselective; endocyclic cleavage; nucleophilic ring opening; ab initio; Organic chemistry; Organisk kemi;

    Abstract : This thesis is a summary of five papers concerning endocyclic cleavage of glycosides and related acetals. Simple lactol ethers undergo endocyclic cleavage to give acyclic chain extended products on treatment with organoaluminium and organotitanium reagents. READ MORE

  4. 22. 1. Asymmetric aldol and alkylation reactions using pyrrolidine-based chiral auxiliaries 2. Syntheses of pine sawfly pheromone precursors and structurally related compounds

    Author : Fredrik Andersson; KTH; []
    Keywords : Chiral auxiliary; Stereoselectivity; Lewis acid; Aldol; Alkylation; Sex pheromone; Pine sawfly; Lipase; Synthesis; Diprion nipponica; Macrodiprion memoralis; Microdiprion pallipes; ;

    Abstract : This thesis describes the syntheses of the 1-propionylatedauxiliaries (S)-(− )-2-(pyrrolidin-2-yl)propan-2-ol and (S)-(− )-2-(1-methoxy-1-methylethyl)pyrrolidine andtheir use in asymmetric aldol and alkylation reactions. Thesynthesis of 1-propionylated (2S,4R) 2-{4-[(tert-butyldimethylsilyl)oxy]pyrrolidin-2-yl}propan-2-olis also described. READ MORE

  5. 23. Natural products from nonracemie building blocks : synthesis of pine sawfly pheromones

    Author : Michael Larsson; Torbjörn Norin; Gunnar Westman; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Organic chemistry; Total synthesis; diastereoselective addition; dimethylzinc; Lewis acid; alkyllithium; Organisk kemi; Organic chemistry; Organisk kemi;

    Abstract : This thesis describes a number of synthetic approaches for obtaining chiral, enantiomerically pure natural products, in particular some semiochemicals. This has been accomplished by using various strategies; by starting from compounds from the chiral pool, by using chiral auxiliaries, via enzymatic resolutions or by chemical asymmetric synthesis. READ MORE

  6. 24. 1. Asymmetric aldol and alkylation reactions using pyrrolidine-based chiral auxiliaries 2. Syntheses of pine sawfly pheromone precursors and structurally related compounds

    Author : Fredrik Andersson; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Chiral auxiliary; Stereoselectivity; Lewis acid; Aldol; Alkylation; Sex pheromone; Pine sawfly; Lipase; Synthesis; Chemistry; Kemi;

    Abstract : .... READ MORE

  7. 25. Development of Lewis acid mediated stereoselective synthesis of nitrogen containing heterocycles

    Author : Åsa Sjöholm Timén; KTH; []
    Keywords : organic chemistry;

    Abstract : This thesis deals with the development of syntheticmethodologies for the preparation of enantio- anddiastereomerically enriched nitrogen-containingheterocycles.Asymmetric Lewis acid mediated Diels-Alder reactions with2H-azirines as dienophiles have been studied. READ MORE