Photochemical ring closure of muconic acid anhydride

A linear correlation between energy of LMCT band and oxygenation reaction rate of a series of catecholatoiron(III) complexes: initial oxygen binding during intradiol catechol oxygenation

“…A 5 mM solution of anthracene in CH 2 Cl 2 (1 mL) was added to the extracted solution and dried over Na 2 SO 4 . The oxidized products were determined by 1 H NMR and mass spectroscopy or by comparison with the literature 1 H NMR data [13,[22][23][24][25][26]. The yields of the products were determined by 1 H NMR spectroscopy using anthracene as the standard.…”

Synthesis of 3‐Azabicyclo[3.2.0]heptane‐Derived Building Blocks via [3+2] Cycloaddition

“…2.0]heptane scaffold using exit vector plot (EVP) tool revealed its structural similarity to either 1,3disubstituted pyrrolidines/piperidines or trans-1,3-disubstituted cyclopentanes/cyclohexanes. Utility of the method was demonstrated additionally by introducing the monoprotected diamine (14) into an automated parallel synthesis, which resulted in 84 % success rate and up to 59 % yield of the library members. Therefore, the developed approach to a set of mono-and bifunctional 3-azabicyclo[3.…”

“…To date, all the aforementioned methods were not adopted for the preparation of bifunctional 1‐substituted 3‐azabicyclo[3.2.0]heptanes, although its isomer – 2‐azabicyclo[3.2.0]heptane‐1‐carboxylic acid has been obtained using a similar transformation, followed by oxidation of the furan ring with NaIO 4 /RuCl 3 . Other known methods for the synthesis of various 3‐azabicyclo[3.2.0]heptane derivatives include imide formation from cyclobutanedicarboxylic acid anhydride,, multicomponent cascade reactions of α,β‐unsaturated aldehydes, N ‐benzylaminocrotonate and secondary amines, and [3+2] cycloadditions. The latter approach is represented by reactions of cyclobutene derivatives with in situ generated oxazolium‐5‐oxides (Scheme , A ) or azomethine ylides, derived either from electrocyclic thermal aziridine ring‐opening ( B ) or deprotonation of iminium species ( C ).…”

“…[5] Other known methods for the synthesis of various 3-azabicyclo[3. 2.0]heptane derivatives include imide formation from cyclobutanedicarboxylic acid anhydride, [14,15] multicomponent cascade reactions of α, -unsaturated aldehydes, N-benzylaminocrotonate and secondary amines, [16] and [3+2] cycloadditions. The latter approach is represented by reactions of cyclobutene derivatives with in situ generated oxazolium-5-oxides [17] (Scheme 1, A) or azomethine ylides, derived either from electrocyclic thermal aziridine ringopening [18] (B) or deprotonation of iminium species [19] (C).…”

Seven‐Membered Heterocycles: Azepines, Benzo Derivatives and Related Systems

“…Cyclization of 1,5-products by a second photoreaction to give the bicyclic systems is a common reaction, but this process can be suppressed completely when the photolysis is carried out at À60 C (6 h, R ¼ Me) and the reaction mixture is allowed to stand at room temperature overnight, yielding only the 1,5-acethyl product in 80%. Oxepine-2,7-diones [323] also undergo photochemical ring closure to the corresponding bicyclic anhydrides (Scheme 21.154).…”