1,721,132 research outputs found
Recent Advances in the Chemistry of Active Methylene Compounds
Full text linkThe peculiar reactivity at methylene group combined with the structural diversity of these classes of compounds is still attracting the interest of scientific community for the development of new and effective methodologies both asymmetric and non-asymmetric. The versatility of these molecules is well highlighted by several recent applications in Michael reactions, aldol additions, in tandem processes etc. or in the synthesis of valuable compounds both under organo- and metal catalysed conditions.
On the basis of these considerations, the aim of this issue is to review recent applications of active methylene compounds focusing on the aspects of the personal research interests of the authors. The contributions can be preferably accounts of personal research work combined with a review of the recent literature
NEW REACTIONS EXPLORING THE CHEMICAL SPACES OF THE ALDOL ADDITION OF ACTIVE METHYLENE COMPOUNDS
No full textOrganic chemists, during research planning and ideas development, intuitively work on the chemical space, even if they are often unaware about the nature and the extent of chemical space of organic reactions in which they are moving. The exploration and the rational analysis of new chemical spaces originating from new tandem and multicomponent aldol addition of active methylene compounds can lead to the development of new efficient and environmentally friendly methodologies and to the synthesis of new libraries of highly functionalised compounds
Enantioselective allylation of aldehydes with allyltrichlorosilane promoted by chiral sulfoxides: a kinetic study
No full textThe allylation of aldehydes is one of the most important methods for C-C bond formation because the obtained homoallylic alcohols are useful building blocks for the synthesis of complex molecules and natural products.1 Particular attention has been devoted to the development of enantioselective versions utilizing chiral allylating reagents, chiral Lewis acids as catalysts and, more recently, chiral Lewis base organocatalysts in the presence of allyltrichlorosilane.1 In the latter case, a wide variety of chiral Lewis bases derived from phosphoramides, N-oxides, sulfoxides, formamides, phosphine oxides, amines and ureas, has been demonstrated to be effective in enantioselective allylation.1
In this context, on the basis of our studies about the use readily available chiral sulfoxides in the allylation of aldehydes with allyltrichlorosilane,2 the peculiarities of this Lewis base have been analyzed from a mechanistic point of view. In this presentation we report a kinetic study in which we have determined kinetic orders with respect to benzaldehyde, silane and (R)-methyl p-tolyl sulfoxide. Moreover conductivity experiments gave us important insights about the species formed during the reaction
Quick and easy access to N-Mannich bases of 1-isoindolinones by catalytic electroactivation of primary and secondary amines and tandem reaction with 2-formylbenzonitriles
Full text linkN-Mannich bases of 1-isoindolinones can be rapidly assembled by
reacting 2-formylbenzonitriles with electroactivated amines on a Pt
cathode, using a catalytic amount of electricity. Usefully, chiral
amines allow the attainment of enantiopure N-Mannich bases by
simple chromatographic separatio
Chiral sulfoxides as activators of allyl trichlorosilanes in the stereoselective allylation of aldehydes
Full text linkChiral aryl methyl sulfoxides proved to be efficient activators in the asymmetric allylation of aldehydes
with allyl trichlorosilanes. High enantioselectivity was found in the case of electron-poor aldehydes. The
high levels of diastereoselectivity and the detection of nonlinear effects have allowed the elucidation of
some mechanistic aspects of the reaction
A Scalable L‐α‐Glycerophosphorylcholine Synthesis through the Automatic pH‐Controlled (R)‐Glycidol Ring Opening with Phosphorylcholine
No full textThe investigation of epoxide ring opening of (R)-glycidol with phosphorylcholine in water leads to the development of an effective synthesis of L-α-glycerophosphorylcholine (L-α-GPC), a commercially available drug. The precise control of reaction pH with an automatic titrator proves to be crucial for achieving conversions of up to 98% and limiting byproduct formation. Additionally, an effective method for the synthesis of phosphocholine as inner salt is reported for the first time, which is also essential for achieving the described results
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