Direct Access to Highly Enantioenriched α-Branched Acrylonitriles through a One-Pot Sequential Asymmetric Michael Addition/Retro-Dieckmann/Retro-Michael Fragmentation Cascade.

A highly enantioselective synthesis of α-branched acrylonitriles is reported featuring a one-pot sequential asymmetric Michael addition/retro-Dieckmann/retro-Michael fragmentation cascade. The method, which relies on a solid, bench-stable, and commercially available acrylonitrile surrogate, is practical, scalable, and highly versatile and provides a direct access to a wide range of enantioenriched nitrile-containing building blocks. Most importantly, the method offers a new tool to incorporate an acrylonitrile moiety in an asymmetric fashion.

O-Allylated Pudovik and Passerini Adducts as Versatile Scaffolds for Product Diversification.

The palladium-catalyzed O-allylation of α-hydroxyphosphonates and α-hydroxyamides obtained from Pudovik and Passerini multicomponent reactions has allowed interesting and highly straightforward access to a variety of building blocks for product diversification. These post-functionalizations include a selective base- or ruthenium hydride-mediated isomerization/Claisen rearrangement cascade and a ring-closing metathesis that allows access to a variety of diversely functionalized phosphono-oxaheterocycles.

Dinucleating Schiff base ligand in Zn/4f coordination chemistry: synthetic challenges and catalytic activity evaluation.

Four Zn/4f polynuclear coordination clusters (PCCs) formulated as [ZnII2DyIII2L2(CO3)2(NO3)2] (1), [ZnIIYIIIL(NO3)2(o-van) (MeOH)] (MeOH) [2 (MeOH)] and [ZnIILnIIIL(NO3)2Cl(EtOH)] where Ln is Dy (3) and Y (4) and where H2L is the dinucleating Schiff base ligand N,N'-bis(3-methoxysalicylidene)cyclohexane-1,2-diamine and o-van is ortho-vanillin, were prepared and fully characterised for the first time. These air-stable heterometallic PCCs, obtained in high yields from commercially available materials, were shown to remain stable in solution in their dinuclear [ZnIILnIIIL] form. Their catalytic activity was evaluated in various catalytic transformations including the Friedel-Crafts alkylation of 2-acyl imidazoles with indoles.

Selective Tsuji-Trost type C-allylation of hydrazones: a straightforward entry into 4,5-dihydropyrazoles.

The 4,5-dihydropyrazole motif has drawn considerable attention over the years as it was shown to exhibit a plethora of biological and pharmacological properties, including anticancer, antibacterial, antifungal, antiviral, and anti-inflammatory properties. As such, it has been the target of a number of methods and drug discovery programs. We report here a straightforward and highly selective approach featuring a key palladium-catalysed Tsuji-Trost type C-allylation and subsequent intramolecular 1,4-addition of hydrazones.

Synthesis of a C(1)-C(23) fragment for spirastrellolide E: development of a mechanistic rationale for spiroketalization.

Synthetic analysis of spirastrellolide E envisioned to entail a cross-metathesis union of the northern and southern hemispheres followed by a Sharpless epoxidation/methylation sequence to achieve the C(22,23) stereogenicity leads to the design of a C(1)-C(23) advanced southern hemisphere exploiting a gold-catalyzed directed spiroketalization as a key step. Stereochemical analysis of this strategic transformation provides insight on the impact of the directing group carbinol stereogenicity on the reaction efficiency and, in turn, permits the conversion of the minor isomer of the spiroketal precursor to the requisite congener for successful spiroketalization.

Non-enzymatic acylative kinetic resolution of primary allylic amines.

A non-enzymatic acetyl transfer-based kinetic resolution of primary allylic amines is reported. The process involves the use of (1S,2S)- in conjunction with a supported ammonium salt and affords the corresponding enantio-enriched N-acetylated allylic amines with unprecedented levels of selectivity (s-factors up to 34).