Polycyclic Indoline-Benzodiazepines through Electrophilic Additions of α-Imino Carbenes to Tröger Bases.

Polycyclic indoline-benzodiazepines can be accessed through the intermolecular reaction of Tröger bases with N-sulfonyl-1,2,3-triazoles. Under Rh catalysis, α-imino carbenes are generated and a subsequent cascade of [1,2]-Stevens, Friedel-Crafts, Grob, and aminal formation reactions yield the polycyclic heterocycles as single isomers (d.r.

Synthesis of Pyrrolidines and Pyrrolizidines with α-Pseudoquaternary Centers by Copper-Catalyzed Condensation of α-Diazodicarbonyl Compounds and Aryl γ-Lactams.

N-aryl γ-lactams react intermolecularly with acceptor-acceptor diazo reagents, usually dicarbonyl compounds, in a copper-catalyzed process to yield functionalized pyrrolidines with α-pseudoquaternary centers. As 1,2-acyl or -phosphoryl migration is preferred, single regioisomers are obtained. Furthermore, in the presence of a Lewis acid, subsequent Friedel-Crafts reactions yield tricyclic pyrrolizidines in excellent yields (90-96 %) and diastereoselectivities (up to >20:1).

A temporary-bridge strategy for enantioselective organocatalyzed synthesis of aza-seven-membered rings.

We report the first enantioselective organocatalyzed domino synthesis of azepane moieties. This temporary-bridge strategy is based on a conceptually original annulation of ambident electrophilic and 1,4-bis-nucleophilic α-ketoamides with 1,3-bis-electrophilic enals. The obtained oxygen-bridged azepanes can be selectively transformed into optically active azepanone, azepanol or azepanedione derivatives of high synthetic value.

α,β-Unsaturated acyl cyanides as new bis-electrophiles for enantioselective organocatalyzed formal [3+3]spiroannulation.

α,β-Unsaturated acyl cyanides are key bis-electrophile substrates for successful domino enantioselective organocatalyzed Michael-intramolecular acylation domino sequences. This new reactivity has been applied to the synthesis of enantioenriched azaspiro[4,5]decanone ring systems by a formal [3+3]spiroannulation, constituting a rare example of synthesis of glutarimides in an optically active form.

Access to polyfunctionalized diquinanes, hydrindanes, and decalines via TiCl4 promoted Michael-aldol and Baylis-Hillman reactions.

The addition of 0.5 equiv of TiCl(4) to (cyclo)alkanones tethered to α,β-unsaturated ketones afforded polyfunctionalized diquinanes, hydrindanes, and decalines. These products, resulting from a Michael-aldol or a Baylis-Hillman reaction, can be obtained with high or total diastereoselectivity in moderate to high yields.

The shortest synthetic route to puromycin analogues using a modified Robins approach.

We are reporting on the utility of commercial vinyl isocyanate for a practical synthetic route from adenosine to N(6)-bis-demethylpuromycin in seven steps and 65% overall yield. A clean one-pot conversion of 3'-bromo-2'-carbamoyl derivative 8 to 3'-amino-3'-deoxyadenosine derivative 10 is the main feature of this synthetic pathway. This synthesis is the shortest synthetic route toward 3'-(aminoacylamido)deoxyadenosines to date.