Ni(ClO(4))(2)·6H(2)O-catalysed regioselective and diastereoselective [3+2]-annulations of aryl oxiranyl-dicarboxylates and indoles via selective C-C bond cleavage of oxirane were revealed. The cycloadditions proceed smoothly with high regio- and diastereoselectivity under mild conditions leading to 1H-furo[3,4-b]indoles in good to excellent yields.

The vicinal amino alcohol is a common motif in natural products and pharmaceuticals. Amino acids constitute a natural, inexpensive, and enantiopure choice of starting material for the synthesis of such functionalities. However, the matters concerning diastereoselectivity are not obvious. This Perspective takes a look in the field of diastereoselective synthesis of vicinal amino alcohols startin...

A novel visible light mediated radical cyclization of enol lactones with difluoroacyl arenes is presented. The reaction experienced a tandem radical cyclization and tolerated a wide range of substrates, resulting in fluorinated γ-butyrolactones in good chemical yield and with excellent diastereoselectivity.

α-Alkyl β-amino esters are available in high diastereoselectivity through a silicon-free Claisen enolate [3,3]-sigmatropic rearrangement of enamide esters. Optimisation studies have probed the crucial role of the initial enolisation and the nature of the enamide N-centre. The demonstration of chirality transfer and the formation of β-proline systems, is also presented.

N-Galactosyl aziridines were synthesized via BF3·OEt2 promoted addition of carbenes generated from diazocarbonyl compounds with O-pivaloylated β-D-galactosylimines in good yields and high diastereoselectivity. The ring-opening reactions with p-toluenethiol of the aziridines provided enantiometrically pure β-S-substituted phenylalanine derivatives in a highly regioselective manner.

A chemoenzymatic synthesis of sialic acid from inexpensive N-acetyl-D-glucosamine is described. In a three-step Wittig-protection-ozonolysis strategy manno-configured aldehydes are obtained. Treatment with oxaloacetate in the presence of macrophomate synthase affords the signature α-keto-γ-hydroxy acid moiety with high diastereoselectivity.

An enantioselective desymmetrization of prochiral 1,3-dinitropropanes has been developed which proceeds via enantiogroup differentiating organocatalytic allylic alkylation. Densely functionalized products with two vicinal stereocenters were obtained generally with good to excellent diastereoselectivity (up to >20 : 1 dr) and superb enantioselectivity (up to >99 : 1 er).

Abstract An efficient stereocontrolled preparation of 2-substituted pyrrolidines and 5-substituted indolizidin-7-ones, by using chiral N-tert-butanesulfinyl imines derived from 4-halobutanal as starting materials, is detailed. Addition Grignard reagents a decarboxylative Mannich­ reaction with β-keto acids involving these proceeded high diastereoselectivity. The synthesis the pyrrolidinic alkal...