Catalytic asymmetric 1,3-dipolar cycloadditions of azomethine ylides have turned out to be one of the most efficient methods for the preparation of enantioenriched pyrrolidines. The past decade has witnessed the development of a bunch of well-defined catalytic systems capable of affording excellent diastereo and enantioselectivities. Recently, a great effort has been focused on expanding the sc...

Guanidinyl pyrrolidines derived from 'S'-proline are effective catalysts for the enantioselective conjugate addition of malonate, nitroalkane and other carbon and heteroatom nucleophiles to cyclohexenone and cyclopentenone in the absence of basic additives. The stereoselectivity is strongly dependent on catalyst loading as well as reaction concentration.

Saturated heterocycles, such as THFs, pyrrolidines, piperidines and THPs, are essential components of many biologically active compounds. Examples of C-H functionalization on these important ring systems remain scarce, especially at unactivated positions. Here we report the development of conditions for the palladium-catalyzed stereoselective C(sp3)-H arylation at unactivated 3-positions of 5- ...

BACKGROUND Tandem olefin metathesis sequences are known to be versatile for the generation of natural product scaffolds and have also been used for ring opening of strained carbo- and heterocycles. In this paper we demonstrate the potential of these reactions for the desymmetrization of 7-azabicycloalkenes. RESULTS We have established efficient protocols for the desymmetrization of different ...

Well-defined unnatural dipeptide-alcohols based on a cis-2,5-disubstitued pyrrolidine backbone were synthesized from commercially available starting materials meso-diethyl-2,5-dibromoadipate, (S)-(-)-1-phenylethylamine, and phenylalaninol. The structures of these unnatural dipeptide-alcohols are supported by HRMS, 1H- and 13C-NMR spectroscopy. These unnatural dipeptide-alcohols can act as build...

A powerful cascade reaction was developed for the synthesis of chromeno[4,3-b]pyrrolidines with high yields and excellent stereoselectivities. This efficient cascade reaction expeditiously established two fused rings which bear three contiguous stereogenic centers including one quaternary stereocenter in a single operation with low catalyst loading under mild conditions.

The L-tert-leucine-derived AmidPhos/silver(I) catalytic system has been developed for the asymmetric [3+2] cycloaddition of azomethine ylides with electronic-deficient alkenes with or without Et3N. Under optimal conditions, highly functionalized endo-4-pyrrolidines were obtained with modest to high yields (up to 99% yield) and enantioselectivities (up to 98% ee).

an important property of electromagnetic fields, which arises from the interaction between fields and chiral molecules, is called optical chirality. by enhancing this field property, while maintaining constant input power, we are able to increase absorption of circularly polarized light by chiral molecules of a certain handedness. this enhancement is achieved through the use of achiral plasmoni...

A common approach in resolving enantiomers of chiral basic drugs by capillary electrophoresis (CE) is to use cyclodextrins (especially their anionic derivatives) as chiral selector in the acidic buffer (pH ≤ 3) in normal or reversed (carrier) mode. Then, some organic modifiers are added to the buffer solution if the resolution is not satisfactory. In case of cetirizine (CTN), applying the same ...