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affording highly substituted cyclopentanes with up to four stereocenters in high yields and selectivities

An asymmetric Diels—Alder reaction of cyclopentenone (I) with a variety of activated 1,2-disubstituted and trisubstituted ethylenes is presented in the presence of the organocatalyst (ORG) and propionic acid as co-catalyst to furnish chiral multifunctionalized norcamphor compounds with high stereoselectivity.

The enantioselective reaction of bromides (I) and (VI) with unsaturated aldehydes (II) followed by reduction or acetalization of intermediate aldehydes gives rise to alcohols (III) or acetals (VIII), which are readily converted into dihydropyran derivatives (V) and (X).

A series of new lanthanide (Ln) silicates have been synthesized using high temperature hydrothermal techniques, and structurally characterized using single crystal and powder X-ray diffraction. The compounds have the general formula NaBa3Ln3Si6O20 (Ln = Y, Nd, Sm, Eu, Gd), and crystallize in the space group Ama2 (No.40). As a representative example, the unit cell parameters of NaBa3Gd3Si6O20 are a = 14.731(3) A, b = 23.864(5) A, c = 5.5449(11) A and Z = 4. The title compounds adopt a three dimensional polar acentric framework made of Ln–O–Si bonding. The framework is comprised of LnO8 and LnO7 units forming edge-sharing infinite chains along the c-axis. These oxy-bridged infinite chains are also linked by [Si4O13] tetrasilicate and [Si2O7] disilicate units to form the three-dimensional framework structure, with Ba2+ and Na+ cations residing inside channels of the framework. The polarity in the structure is imparted by the unusual tetrasilicate arrangement. The luminescence and magnetic properties were investigated on selected compounds. The temperature dependent magnetic susceptibility measurements on the Nd, Sm, and Gd derivatives reveal a Curie–Weiss behavior with an antiferromagnetic coupling parameter. For the Eu-derivative, the temperature dependent magnetic susceptibility deviates significantly from Curie–Weiss behavior. Luminescence properties of NaBa3Eu3Si6O20 and NaBa3Sm3Si6O20 compounds exhibited the characteristic transitions of Eu3+ (5D0 → 7FJ, J = 0–4) and Sm3+ (4G5/2 → 6HJ, J = 5/2, 7/2), respectively, leading to strong visible red and orange emissions, respectively.

A wide range of optically active chromans are highly regio- and stereoselectively obtained utilizing a novel asymmetric 1,6-Friedel—Crafts/1,4-oxa-Michael cascade reaction of hydroxyarenes with 2,4-dienals.

Enamine-activated aldehydes are added to p-quinone methides to yield aldehydes with two contiguous stereocenters with good diastereo- and excellent enantioselectivity.

This method yields the title compounds with four contiguous stereocenters with moderate to good diastereo- and enantioselectivity.

Vinyl phosphonates (II) and (VIII) as well as nitro olefins (XI) and (XIII) react with annulated cyclic enals (I), (IV), (VI) and (X) to carbocyclic derivatives (III), (V), (VII), (IX), (XII), and (XIV) in a highly regio- and enantioselective manner using proline-based derivatives as chiral catalysts.

Functionalized hydroisochromenes (III), (V) and chromenes (VII) are enantioselectively obtained by trienamine-mediated [4+2]-cycloaddition/nucleophilic ring-closing or iminium-ion/aminal-mediated oxa-Michael/Michael/nucleophilic ring-closing reactions of 2-nitroallylic alcohols (II).

A novel enantioselective one-pot synthesis of bridged benzoxazocines from salicylaldehydes, anilines, and α,β-unsaturated aldehydes using a L-prolinol derivative as catalyst is presented.

α,β-Unsaturated aldehydes with conjugated substituents as well as unsaturated alkyl chains give unsatisfactory results.

The presented reaction, catalyzed by a bifunctional squaramide containing aminocatalyst is applicable to aliphatic, as well as aromatic α,β-unsaturated acyl phosphonates bearing electron-withdrawing or donating substituents to give good to high yields and good enantioselectivities.

An organocatalytic cascade reaction mediated trienamine [4 + 2]-cycloaddition/nucleophilic ring-closing sequence is developed.

A facile one-pot protocol for the synthesis of steroids via Diels—Alder reaction of enals with cyclic dienophiles in the presence of catalytic amounts of Tms-diphenylprolinol (PRS) is developed.

The radical reduction of a variety of substrates, e.g. halogenides (V) and (VII), is achieved using (Tms)3SiH as hydride source and air or light as radical initiator.

Based on a trienamine-mediated H-bond directed [4 + 2] cycloaddition of 2,4-dienals and 1,4-naphthoquinones a stereoselective approach to enantioenriched carboannulated naphthoquinones and dihydronaphthoquinones is developed.

The new concept presented here is developed for the unprecedented intermolecular enantioselective organocatalyzed vinylogous 1,6-addition to linear 2,4-dienals.