10.1002/anie.201508331
This study investigates the gold(I)-catalyzed enantioselective desymmetrization of 1,3-diols via intramolecular hydroalkoxylation of allenes. The key chemicals involved include the catalyst system 3-F-dppe(AuCl)2/(R)C8-TRIP Ag, which is particularly effective in promoting the desymmetric cyclization of 2-aryl-1,3-diols. The 3-F-dppe ligand plays a crucial role in enhancing the enantioselectivity and diastereoselectivity of the reaction. The (R)C8-TRIP counteranion is also crucial in achieving high enantioselectivity. The tested substrates vary in the substituents on the allene moiety and the aromatic ring, and the study shows good tolerance to different functional groups and ring sizes. The resulting products are polysubstituted tetrahydrofurans containing two stereocenters, which can be further transformed into various derivatives, demonstrating the synthetic potential of this approach.
10.1007/BF00952390
The study investigates the telomerization of propadiene by morpholine, using a binary catalytic system composed of PdCl2 and triphenylphosphine. The primary product formed is N-(2,3-dimethylenebutyl)morpholine, with a yield of approximately 49.5%, and a small amount of allylmorpholine is also produced. Nonaminated propadiene oligomers are observed as by-products. The addition of a reducing agent, NaBH4, enhances the catalytic activity without significantly altering the selectivity. However, the introduction of CF3COOH, which is used as an activating additive in the amination of butadiene, decreases the yield and shifts the selectivity towards the formation of heavier products. The study also explores the effects of varying the initial concentration of morpholine and the ratio of propadiene to morpholine, finding that these factors significantly influence the reaction rate and the isomeric composition of the products. The presence of conjugated double bonds in the hydrocarbon substituent of the product allows for further conversion into high-molecular-weight products.
10.1002/asia.201200201
The research presents a ruthenium(II)-catalyzed intramolecular [2+2+2] cyclization of allene-yne-enes to construct fused-tricyclic skeletons. The reaction involves the use of a [Cp*RuCl(cod)] catalyst with various substrates to form tricyclic compounds in a stereoselective manner. The study investigates the effects of different substituents on the allene and alkene moieties, as well as the linker structure, on the yield and stereochemistry of the products. Experiments were conducted with various allene-yne-ene substrates, and the yields and stereochemistry of the resulting tricyclic compounds were analyzed. Techniques such as X-ray crystallographic analysis and NOESY experiments were employed to determine the stereochemistry of the products. The reaction mechanism is proposed to involve the formation of a ruthenacyclopentene intermediate, followed by insertion of the unsaturated bond and reductive elimination to afford the tricyclic compounds.
10.3762/bjoc.6.33
The research presents a novel synthetic approach to C3-carbocyclic spirooxindoles using a thermal tandem [3,3]-sigmatropic rearrangement/[2 + 2] cycloaddition reaction. The purpose of this study was to develop a concise and efficient method to synthesize densely functionalized spirooxindoles, which are rare structural motifs with potential applications in pharmaceuticals and natural product synthesis. The reaction involves a thermal [3,3]-sigmatropic rearrangement of propargylic acetates to form allenyl acetates, which then undergo a [2 + 2] cycloaddition with an alkyne to produce the desired spirooxindoles. The study concluded that this tandem reaction is highly selective for the distal double bond of the allene, even with densely functionalized substrates, and provides a rapid increase in molecular complexity. The method is tolerant of various functional groups and can be performed in solvents like 1,2-dichlorobenzene or N-methylpyrrolidinone. The research demonstrates a rare example of a thermal [3,3]-sigmatropic rearrangement of a propargylic acetate, expanding the synthetic utility for accessing complex spirooxindole architectures.
F+, 
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