Stille coupling of an aziridinyl stannatrane.

An aziridinyl stannatrane 8 couples with aryl or alkenyl halides RX under modified Stille conditions to afford substituted aziridines. Efficient coupling at room temperature is possible in the best examples in the presence of ((t)Bu3P)2Pd and CuOP(O)Ph2 (CuDPP).

Novel C-1 substituted cocaine analogs unlike cocaine or benztropine.

Despite a wealth of information on cocaine-like compounds, there is no information on cocaine analogs with substitutions at C-1. Here, we report on (R)-(-)-cocaine analogs with various C-1 substituents: methyl (2), ethyl (3), n-propyl (4), n-pentyl (5), and phenyl (6). Analog 2 was equipotent to cocaine as an inhibitor of the dopamine transporter (DAT), whereas 3 and 6 were 3- and 10-fold more potent, respectively.

Enantioselective synthesis of cocaine C-1 analogues using sulfinimines (N-sulfinyl imines).

The first examples of cocaine analogues having substituents (methyl, ethyl, n-propyl, n-pentyl, and phenyl) at the C-1 position of the cocaine tropane skeleton were prepared by heating sulfinimine-derived α,β-unsaturated pyrrolidine nitrones. In the presence of the Lewis acid Al(O(t)Bu)(3) the nitrones undergo an intramolecular [3 + 2] cycloaddition to give tricyclic isoxazolidines that were transformed in three steps to the cocaine analogues. In the absence of the Lewis acid, lactams were formed resulting from rearrangement of the nitrone to an oxaziridine.

Asymmetric total synthesis of (S)-(+)-cocaine and the first synthesis of cocaine C-1 analogs from N-sulfinyl β-amino ester ketals.

Sulfinimine-derived α,β-unsaturated pyrrolidine nitrones, on heating with Al(O-t-Bu)(3), undergo a highly stereoselective intramolecular [3 + 2] cycloaddition to give tricyclic isoxazolidines, which are transformed in three-steps to give C-1 substituted cocaine analogs.

Asymmetric synthesis of cyclic cis-beta-amino acid derivatives using sulfinimines and prochiral Weinreb amide enolates.

Cyclic cis-beta-amino Weinreb amides, valuable building blocks for the asymmetric synthesis of cyclic beta-amino acids derivatives, are readily prepared via ring-closing metathesis of sulfinimine-derived N-sulfinyl beta-amino diene Weinreb amides. These unsaturated cyclic cis-beta-amino Weinreb amides are valuable building blocks for the asymmetric synthesis of cyclic beta-amino acid derivatives.

Asymmetric synthesis of substituted tropinones using the intramolecular mannich cyclization reaction and acyclic N-sulfinyl beta-amino ketone ketals.

Sulfinimine-derived, enantiopure N-sulfinyl beta-amino ketone ketals on hydrolysis give dehydropyrrolidine ketones that on treatment with (Boc)(2)O/DMAP afford substituted tropinones in good yield.

Selective peptide binding using facially amphiphilic dendrimers.

Amphiphilic dendrimers, which contain both hydrophobic and hydrophilic groups in every repeat unit, exhibit environment-dependent assemblies both in hydrophilic solvent, water, and in lipophilic solvent, toluene. Upon investigating the status of these assemblies in a mixture of immiscible solvents, these dendrimers were found to be kinetically trapped in the solvent in which they are initially assembled. This property has been exploited to selectively extract peptides from aqueous solution into an organic phase, where the peptides bind to the interior functionalities of the dendritic inverse micelles.