Highly diastereoselective bicyclizations of aminodienes catalyzed by chelating diamide complexes of Sc(III) and Y(III) that lead to pyrrolizidines and indolizidines are described. This bis(annulation) procedure has been utilized in a concise synthesis of the pyrrolizidine alkaloid 195F.

From a series of N,N'-disubstituted-1,1'-binaphthyl-2,2'-diamines, several group 3 metal complexes were synthesized via an in situ procedure. These chiral complexes were subsequently applied to catalysis of intramolecular alkene hydroamination. Significant structure-activity relationships were observed, most notably a reversal of stereoselectivity for cyclopentyl versus diphenylmethyl substituents.

The Diels-Alder reaction is a cornerstone in organic synthesis, forming two carbon-carbon bonds and up to four new stereogenic centers in one step. No naturally occurring enzymes have been shown to catalyze bimolecular Diels-Alder reactions. We describe the de novo computational design and experimental characterization of enzymes catalyzing a bimolecular Diels-Alder reaction with high stereoselectivity and substrate specificity. X-ray crystallography confirms that the structure matches the design for the most active of the enzymes, and binding site substitutions reprogram the substrate specificity. Designed stereoselective catalysts for carbon-carbon bond-forming reactions should be broadly useful in synthetic chemistry.

We report a highly regioselective metal-free oxidative cyclization of sulfonamides onto tethered, unactivated alkenes using hypervalent iodine and Brønsted acids. Under these conditions the acid counterion is incorporated into the cyclized products providing an overall aminotrifluoroacetoxylation of the alkene. An unusual preference for endo ring closure is exhibited in contrast to existing exo selective methods. Multiple ring sizes can be formed to access functionalized pyrrolidines, piperidines, and azepanes with a general preference for endo cyclization. A variety of substrate substitution patterns were tolerated to provide nitrogen-containing heterocycles with high regioselectivities and good to excellent diastereoselectivities.