58195-50-9Relevant articles and documents
Poly(methylhydrosiloxane) as a reductant in the catalytic base-free Wittig reaction
Longwitz, Lars,T?njes, Jan,Werner, Thomas
, p. 4852 - 4857 (2021/07/12)
Herein, we report a catalytic, base-free Wittig reaction forming highly functionalized alkenes with PMHS as a terminal reductant and butylacetate as a green solvent. Poly(methylhydrosiloxane) (PMHS) is a non-toxic, enviromentally friendly, inexpensive and easy to handle reductant. However, the inherent low reactivity hampers its applicability in catalytic reactions, such as P(iii)/P(v) redox cycling reactions. Most of these catalytic systems include highly active aryl silanes to facilitate phosphane oxide reduction and are not compatible with PMHS or similar more sustainable terminal reductants. The herein reported catalyst system which is based on a methyl-substituted phosphetane operates at low catalyst loadings without additional co-catalysts and allowes the use of PMHS as terminal reductant. A wide variety of functional groups was tolerated and 25 different alkenes were synthesized in yields up to 96% with excellent stereoselectivity. Mechanistic studies revealed the formation of water from silanol condensation as the main pathway of siloxane formation.
Phosphine-Catalyzed Reaction between 2-Aminobenzaldehydes and Dialkyl Acetylenedicarboxylates: Synthesis of 1,2-Dihydroquinoline Derivatives and Toward the Development of an Olefination Reaction
Han, Xu,Saleh, Nidal,Retailleau, Pascal,Voituriez, Arnaud
supporting information, p. 4584 - 4588 (2018/08/09)
A series of 1,2-dihydroquinolines were synthesized in good to excellent yields by reacting 2-aminobenzaldehyde derivatives and dialkyl acetylenedicarboxylates with catalytic amounts of phosphine. This reaction was rendered catalytic by the selective in situ phosphine oxide reduction with the use of phenylsilane. Furthermore, with the same starting materials and with an additional role of the reducing agent, a new olefination reaction was discovered. Hydrogen/deuterium (H/D) exchange experiments revealed the possible mechanism of this reaction.
First Base-Free Catalytic Wittig Reaction
Schirmer, Marie-Luis,Adomeit, Sven,Werner, Thomas
supporting information, p. 3078 - 3081 (2015/06/30)
The first base-free catalytic Wittig reaction utilizing readily available Bu3P (5 mol %) as an organocatalyst is reported. The initial Michael addition of the phosphine to a suitable acceptor substituted alkene ultimately results in the formation of an ylide which is subsequently converted with an aldehyde. The presented 1H NMR studies actually reveal evidence for the Michael addition and proposed ylide formation. Under the optimized reaction conditions various maleates and fumarates were converted with aromatic, heteroaromatic, and aliphatic aldehydes to evaluate the scope and limitations of this unprecedented reaction. Notably, maleates and fumarates react in a stereoconvergent fashion. The corresponding products were obtained in up to 95% isolated yield and E/Z-selectivities up to 99:1.
