Cationic organic intermediates participate in a wide variety of useful synthetic transformations, but their high reactivity can render selectivity in competing pathways difficult to control. Here, we describe a strategy for inducing enantioselectivity in reactions of protio-iminium ions, wherein a chiral catalyst interacts with the highly reactive intermediate through a network of noncovalent i...

A general three-component triple cascade reaction through an iminium-enamine-iminium sequential activation initiated by a hetero-Michael addition to α,β-unsaturated aldehydes affords [3.2.0]heterobicycles in high diastereoselectivity. The rate and diastereoselectivity of the reaction depended on the (E)-4-heterocrotonate and size of the secondary amine. The enantiomers of the major diastereoiso...

An alpha hydroxy pyrrolidine tricyclic nucleoside 3 and its spontaneous reaction with acetone is described. In this transformation highly functionalized polycyclic nucleosides with rather unusual molecular skeletons are formed in a complete regio- and stereoselective way. The reaction involves the formation of three new bonds, two of them novel carbon-carbon bonds, in a one-pot way. An enamine-...

Small molecules that can specifically bind to a DNA abasic site (AP site) have received much attention due to their importance in DNA lesion identification, drug discovery, and sensor design. Herein, the AP site binding behavior of sanguinarine (SG), a natural alkaloid, was investigated. In aqueous solution, SG has a short-wavelength alkanolamine emission band and a long-wavelength iminium emis...

The key steps in most organocatalytic cyclizations are the reactions of electrophiles with nucleophiles. Their rates can be calculated by the linear free-energy relationship log k(20 °C) = s(N)(E + N), where electrophiles are characterized by one parameter (E) and nucleophiles are characterized by the solvent-dependent nucleophilicity (N) and sensitivity (s(N)) parameters.Electrophilicity param...

Borane mediated hydride abstraction of amines efficiently generates useful iminium salts. This review explores this fascinating reactivity and discusses how the intermediates are utilised in a variety stoichiometric catalytic processes.

BACKGROUND Sanguinarine (SA) is a quaternary benzo[c]phenanthridine alkaloid that is mainly present in the Papaveraceae family. SA has been extensively studied because of its antimicrobial, anti-inflammatory, antitumor, antihypertensive, antiproliferative and antiplatelet activities. Metabolic studies demonstrated that SA bioavailability is apparently low, and the main pathway of SA metabolism ...

The structure of the title compound, [Ph(3)P=N=PPh(3)](+)[Ph(3)SnCl(2)](-) or (C(36)H(30)NP(2))[Sn(C(6)H(5))(3)Cl(2)], obtained as a by product of the reaction between Ph(3)SnCl and [Ph(3)P=N=PPh(3)](+)·HSeO(3) (-), consists of discrete essentially isolated ions. Both the cation and the anion lie on twofold axes which pass through the central N atom in the cation and through the Sn(IV) atom in ...

Phosphorus-based Mannich-type reactions (phospha-Mannich reactions) of primary or secondary phosphines with carbonyl compounds and amines (R2NH, RNH2, NH3) provide a powerful synthetic tool in the worldwide search for future ligands. The variety available allows designing fine-tuning water-soluble, chiral, macrocyclic, pincer, tripodal, photoactive, etc., phosphine ligands P–C–N linkage(s) (P,N...