A Simple Route tocis- andtrans-Bis-σ-homobenzenes

Abstract

Keywords: Azo compounds / Aromaticity / Photolysis / Rearrangements / Bis-σ-homobenzenesPhotolysis of tetracyclic azo compounds 15, readily available from [4+2] cycloaddition between 1,2,4,5-tetrazines and cyclopropenes, gives access to cis-and trans-bis-σ-homoben-

Access to cyclohexadiene and benzofuran derivatives via catalytic arene cyclopropanation of α-cyanodiazocarbonyl compounds

“…On this basis, the anti-relationship of the cyclopropane rings was proposed for both products according to the non-observation of 4 J H4–H6 coupling, a feature that was reported for trans -bis- ó -homobenzenes by Sauer et al . 29 In addition, the exo - and endo -orientation of the C-8 carboxylate group was, respectively, assigned to 3a and 3a′ based on the relatively smaller and larger values of the coupling constants between H-8 and H-1/H-7 ( 3a : J H1–H8 = 4.2 Hz, J H7–H8 = 4.1 Hz/ 3a′ : J H8–H1 = 8.8 Hz, J H8–H7 = 8.8 Hz). 30 The stereochemistry was further supported by 1 H– 1 H NOESY correlations as illustrated in Scheme 3.…”

Lewis Acid Catalyzed Inverse Electron-Demand Diels−Alder Reaction of 1,2-Diazines

“…Using this protocol, even linear ketones can be transformed, where the enamine is difficult to isolate . Also less activated dienophiles, like dihydrofurans, give in moderate to good yield the substituted naphthalenes . Alkynes were, so far, not reactive in the catalyzed IEDDA reaction.…”