Dibenzoxazepinium Ylides: Facile Access and 1,3-Dipolar Cycloaddition Reactions

Synthesis of tetracyclic dibenzo[b,f][1,4]oxazepine-fused β-lactams via visible-light-induced Staudinger annulation

An efficient visible-light-induced Staudinger [2 + 2] annulation reaction between α-diazo ketones and dibenzo[b,f][1,4]oxazepine/thiazepine-imines under catalyst-free conditions has been developed. This protocol provides a facile method to synthesize tetracyclic dibenzo[b,f][1,4]oxazepine/thiazepine-fused β-lactams bearing a quaternary carbon center with a broad substrate scope and high efficiency (37 examples, up to >99% yield).

A simple route to tetracyclic oxazepine-fused pyrroles via metal-free [3+2] annulation between dibenzo[b,f][1,4]oxazepines and aqueous succinaldehyde

A direct method for the synthesis of tetracyclic oxazepine-fused pyrroles has been developed through [3+2] annulation between aqueous succinaldehyde and dibenzo[b,f][1,4]oxazepines under metal-free conditions.

One-Pot Synthesis of Chiral Tetracyclic Dibenzo[ b, f][1,4]oxazepine-Fused 1,2-Dihydropyridines (DHPs) under Metal-Free Conditions

An efficient protocol for the catalytic asymmetric synthesis of new dibenzo[ b, f][1,4]-oxazepine-fused 1,2-dihydropyridines (DHPs) has been described under metal-free conditions. This reaction proceeds through proline-catalyzed direct Mannich/cyclization between seven-membered dibenzo[ b, f][1,4]-oxazepine-imines and aqueous glutaraldehyde, followed by IBX-mediated site-selective dehydrogenative oxidation in one-pot operation with high yields (up to 92%) and excellent enantioselectivity (up to >99:1 er).

Ru-Catalyzed asymmetric transfer hydrogenation of substituted dibenzo[b,f][1,4]oxazepines in water

A phosphine free, additive free catalytic ATH protocol of dibenzo[b,f][1,4]oxazepine compounds using an (R,R)-Ru-Ts-DPEN complex was developed for the first time using HCOOH–HCOONa as a green hydrogen source.

Selective synthesis of cis- and trans-2-(methyl/phenyl)-3-(trifluoromethyl)aziridines and their regio- and stereospecific ring opening

A convenient and stereoselective approach toward cis- and trans-1-alkyl-2-(methyl/phenyl)-3-(trifluoromethyl)aziridines was developed starting from the corresponding α,α,α-trifluoroketones via imination, α-chlorination, and hydride-induced ring closure. The reactivity of these newly synthesized nonactivated α-CF3-aziridines was evaluated by applying N-protonation or N-alkylation to effect regio- and stereospecific aziridine ring opening by oxygen, halogen, sulfur, and nitrogen nucleophiles. Furthermore, nonactivated α-CF3-aziridines were easily transformed into their activated analogues by replacing the N-benzyl protecting group with a N-tosyl group, rendering these α-CF3-aziridines much more susceptible to nucleophilic ring opening.