Die organisch-chemische Synthese hat stets eine grose Faszination auf den Chemiker ausgeubt, und sie wird auch in Zukunft nichts von ihrer Bedeutung verlieren. Es ist eine Binsenweisheit, das alle Chemiker - und nicht nur die - auf die Synthese chemischer Verbindungen, mit denen sie arbeiten wollen, angewiesen sind. So ist die organisch-chemische Synthese heute mehr denn je die Schnittstelle von Organischer Chemie, Biologie. Biochemie, Medizin, Physik und Materialwissenschaft. Man sollte auch nicht vergessen, das die Grundlage der chemischen Industrie die Synthese ist. Fur den Synthetiker aus Leidenschaft aber ist die Synthese weit mehr als nur Mittel zu dem Zweck, Verbindungen in die Hand zu bekommen; sie ist Ausdruck seiner Kreativitat. Intelligenz und seines handwerklichen Konnens, aber auch seiner Ausdauer.

Sequentielle Transformationen in der Organischen Chemie eine Synthesestrategie mit Zukunft

The reaction of allylstannanes 1 with aldehydes 2 in THF was catalyzed by Pd(II) or Pt(II) complexes (10 mol %) either at room temperature or at reflux, giving the corresponding homoallylic alcohols 3 in high to good yields. Among the catalysts examined, PtCl2(PPh3)2 gave the best result. No only allyltribitylstannane but also methallyl- and crotyltributylstannane could be utilized in this transition metal catalyzed reaction. Detailed mechanistic studies of the Pd(II)-catalyzed allylation, using NMR spectroscopy, revealed that the bis-π-allylpalladium complex is a key intermediate for the catalytic cycle and it exhibits nucleophilic reactivity. The nucleophilic reactivity of the intermediate is in marked contrast to the electrophilic reactivity of ordinary π-allylpalladium complexes (π-allylPdX, X = OAc, halogen, OCO2R, etc.). The addition of allyl-, crotyl-, and methallylstannanes to various imines 4 proceeded very smoothly to give the corresponding allylated products (homoallylic amines 5) in good to hi...

Palladium- and Platinum-Catalyzed Addition of Aldehydes and Imines with Allylstannanes. Chemoselective Allylation of Imines in the Presence of Aldehydes

The molecular structures and spectral properties of α-haloketones as well as their syntheses are analyzed and reviewed. Their reactivity towards oxygen, nitrogen, and sulfur nucleophiles, carboxylic acids, carbon nucleophiles, alkenes, and alkynes are discussed.

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The Chemistry of α-Haloketones and Their Utility in Heterocyclic Synthesis

Nitrile anion cyclizations

Olefination of aromatic and aliphatic aldehydes with ethyl diazoacetate was achieved in excellent yields with triphenylphosphine and catalytic amounts of iron(II) meso-tetra(p-tolyl)porphyrin. The reaction conditions are mild and the process is efficient and highly selective (>90%) for the synthesis of the trans-olefin isomer. Results of mechanistic studies are discussed.

https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1766&context=chem_pubs

A New and Efficient Method for the Selective Olefination of Aldehydes with Ethyl Diazoacetate Catalyzed by an Iron(II) Porphyrin Complex

Barbier-type reaction with trialkylstibine 1

A Novel Olefination of Carbonyl Compounds with α-Bromoacetic Ester Mediated by Tri-n-butylstibine.

Studies of the use of elemento-organic compounds of the fifteenth and sixteenth groups in organic synthesis. LXXI: Reaction of α-halogeno carboxylic derivatives with carbonyl compounds promoted by tributylstibine

A new method for the synthesis of cyclopropane with three electron-withdrawing groups

Tributylstibine can mediate the olefination of carbonyl compounds with bromomalonic ester and with dibromomalonic ester. An initial halophilic attack of tributylstibine on the bromine of bromomalonic or dibromomalonic ester forming an ion pair of bromotributylstibonium cation and malonic (A) or bromomalonic ester carbanion (B), respectively, is proposed. These ion pairs react with carbonyl compounds to achieve subsequent olefination. Alternatively, 2 equiv of A collapse, with elimination of malonic ester, to form stiborane D, and the ion pair B reacts with another equivalent of tributylstibine to form stiborane D. This last undergoes a Wittig-type reaction with carbonyl compound to achieve olefination.

Tributylstibine‐mediated olefination of carbonyl compounds with bromomalonic ester and with dibromomalonic ester—A possible pathway through a stibonium ylide via halophilic initiation by tertiary stibines

Chen Chen

Papers

Barbier-type reaction with trialkylstibine 1

A Novel Olefination of Carbonyl Compounds with α-Bromoacetic Ester Mediated by Tri-n-butylstibine.

Studies of the use of elemento-organic compounds of the fifteenth and sixteenth groups in organic synthesis. LXXI: Reaction of α-halogeno carboxylic derivatives with carbonyl compounds promoted by tributylstibine

A new method for the synthesis of cyclopropane with three electron-withdrawing groups

Tributylstibine‐mediated olefination of carbonyl compounds with bromomalonic ester and with dibromomalonic ester—A possible pathway through a stibonium ylide via halophilic initiation by tertiary stibines