The (-)-S isomer of 5-benzoyl-1,2-dihydro-3H-pyrrolo[1,2-alpha]pyrrole-1-carboxylic acid is about 60 times more potent than the (+)-R isomer in the carrageenan edema test and ca. 230 times more active than the (+)-R isomer in the mouse phenylquinone writhing assay.

An efficient monoalkylation of primary amines with primary or secondary alcohols catalyzed by Ra-Ni under mild conditions is described.

Organocatalysis is a growing area that is benefiting from advances in many fields. Its implementation has begun in areas such as supramolecular chemistry, organic chemistry and natural product synthesis. While a considerable number of important publications in the field of organocatalytic Mukaiyama-type additions have been reported, they are yet to be fully covered in a review. Therefore, we would like to highlight the applications of various kinds of organocatalysts in Mukaiyama-type reactions, while also including the vinylogous Mukaiyama variation. Herein we describe and discuss the development and current state of the art of the organocatalytic Mukaiyama reaction, vinylogous Mukaiyama and related reactions.

The Friedel-Crafts reaction of methyl alkyl- and arylsulfinates with aromatic systems, activated by one or more electron-donating substituents (OH, OMe, NHR, NR(2)), provides alkyl aryl and diaryl sulfoxides under mild conditions and in moderate to good yields. The very high regioselectivity usually observed in these sulfinylation reactions is rationalized on the basis of a Wheland intermediate having a trigonal bypyramidal structure in which steric and electronic interactions are significant factors strongly destabilizing the attack to the ortho positions.

Optically pure (S)-(-)-xylopinine 2 was prepared in three steps in 52% overall yield. Thus, condensation of the carbanion derived from (S)-4 with the (S)-(E)-sulfinylimine 5 gave a 2:1 mixture of tetrahydroisoquinolines 6a and 6b, differing only in configuration at sulfur. N-Desulfinylation of this mixture gave the diastereomeric sulfoxides which, without separation, were converted into (S)-(-)-xylopinine (2) with loss of the sulfinyl moieties under Pictet-Spengler conditions. This unprecedented ipso electrophilic substitution of a sulfinyl group may have synthetic implications beyond that described in this work.