Ring-Opening and -Expansion of 2,2′-Biaziridine: Access to Diverse Enantiopure Linear and Bicyclic Vicinal Diamines

Tandem (4 + 3)-Annulation of Aziridines: Stereoselective Access to Fused Azepinoindoles

A stereoselective tandem (4 + 3)-coupling of aziridines with 4-alkylidene indole malonates has been disclosed under Cu-catalysis involving a base-promoted annulation. The methodology serves as a potential approach toward the facile construction of fused azepinoindoles with good yields and diastereoselectivities. Late-stage natural product and drug modification as well as preliminary investigations for the enantioselective (4 + 3)-annulation are important practical features.

The Detosylation of Chiral 1,2-Bis(tosylamides)

The deprotection of chiral 1,2-bis(tosylamides) to their corresponding 1,2-diamines is mostly unsuccessful under standard conditions. In a new methodology, the use of Mg/MeOH with sufficient steric additions allows the facile synthesis of 1,2-diamines in 78-98% yields. These results are rationalized using density functional theory and the examination of inner and outer-sphere reduction mechanisms.

A synthetic route to 1,4-disubstituted tetrahydro-β-carbolines and tetrahydropyranoindoles via ring-opening/Pictet–Spengler reaction of aziridines and epoxides with indoles/aldehydes

A route to 1,4-disubstituted tetrahydro-β-carbolines and tetrahydropyrano[3,4-b]indoles in high yields and stereoselectivity via S_N2-type ring opening/Pictet–Spengler reaction of aziridines and epoxides with indoles is described.

Synthesis and Density Functional Theory Studies of Azirinyl and Oxiranyl Functionalized Isoindigo and (3Z,3'Z)-3,3'-(ethane-1,2-diylidene)bis(indolin-2-one) Derivatives

The design and synthesis of functionalized isoindigo compounds by reaction of isoindigo with (S)-glycidyl tosylate, epibromohydrin, 2-(bromomethyl)-1-(arylsulfonyl)aziridine, and 2-(bromomethyl)-1-(alkylsulfonyl)aziridine in the presence of MeONa proceed under mild conditions in moderate yields. (3Z,3’Z)-3,3’-(Ethane-1,2-diylidene)bis(1-(oxiran-2-ylmethyl)indolin-2-one), with an extended central olefin π-conjugated moiety was also reacted with methyl-oxiranes to give the corresponding N,N’-disubstituted derivative. Calculations with DFT and TD-DFT of hypothetical isoindigo-thiophene DA molecules with various electron withdrawing substituents, including aziridine, oxirane, nitrile, carbonyl, and sulfonate, indicated that the proximity and strength of the functional group have a significant effect on the HOMO, LUMO, vertical excitation energy, and oscillator strength of the π–π* transitions.

Cascade reactions of indigo with oxiranes and aziridines: efficient access to dihydropyrazinodiindoles and spiro-oxazocinodiindoles

Cascade reactions of indigo with strained electrophiles affords access to previously unknown oxazocino, pyrazino, and diazepino diindoles with selective anti-plasmodial activity.

Phenolate-induced intramolecular ring-opening cyclization of N-tosylaziridines: access to functionalized benzoxacycles

Phenolate-induced, diastereo- and regioselective intramolecular exo-tet ring-opening cyclization of N-tosylaziridines has been achieved for the first time.

Palladium-Catalyzed Cross-Coupling of N-Sulfonylaziridines and Alkenylboronic Acids: Stereospecific Synthesis of Homoallylic Amines with Di- and Trisubstituted Alkenes

A palladium-catalyzed cross-coupling of 2-alkylaziridines with alkenylboronic acids to give homoallylamines is presented. The reaction is highly regioselective and stereospecific and provides convenient access to enantioenriched amines with 1,1-disubstituted, 1,2-disubstituted, and trisubstituted alkenes. The modular synthesis of a 2,5-disubstituted pyrrolidine natural product was completed in three steps and 67% overall yield.

Breaking aziridines to construct morpholines with a gold(i)-catalyzed tandem ring-opening and cycloisomerization reaction

A convenient synthetic method for the construction of morpholine derivatives from easily available aziridines and propargyl alcohols has been successfully developed. A tandem nucleophilic ring-opening of aziridine/6-exo-dig cyclization/double bond isomerization sequence was achieved by using a single gold(i) catalyst under mild conditions. The gold(i) catalyst served as a π acid and also a σ acid to realize the dual activation of both reactants in this reaction. The obtained unsaturated morpholine products could be easily hydrogenated to achieve target morpholine derivatives with good diastereoselectivities in high yields.