Pyrroles as terminators in cationic cyclizations. The preparation of 5,6,7,8-tetrahydroindolizidines and 6,7,8,9-tetrahydro-5H-pyrrolo[1,2-a]azepines

Cyclialkylation of Arylalkyl Epoxides with Solid Acid Catalysts

“…13 C-NMR signals were assigned by the attached proton test 2.6, Al/Na ϭ 2.9). Ϫ Montmorillonite K10 (Si/Al ϭ 5.1, Al/Na ϭ 69 (100), 68 (16), 65 (14). Ϫ The crude alkene was epoxidised with MCPBA (molar ratio peroxyacid/alkene ϭ 1.4) affording epoxide 45) was purchased from Fluka.…”

“…Ϫ 1 (m, 4 H). (18), 91 (19), 78 (20), 77 (14). was obtained by epoxidation of the corresponding alkene with Cyclialkylation and Rearrangement Products from 2-Methyl-5-phe-…”

Synthesis of Dihydropyrrolizine and Tetrahydroindolizine Scaffolds from Pyrroles by Titanocene(III) Catalysis

“…The epoxide 1 (Table ) is an especially appealing substrate for the evaluation of our concept. Tanis and Raggon have shown that a ZnI 2 ‐mediated (2 equiv in C 6 H 6 ) S N 2 reaction of 1 yields the tetrahydroindolizine derivative 2 (74 %) . Our titanocene(III)‐catalyzed reactions proceed by ET and leads to the dihydropyrrolizine 3 in 86 % yield.…”

Cyclialkylation of Arylalkyl Epoxides with Solid Acid Catalysts

“…All glassware was dried at 140°C for at least 1 h prior to use in the catalytic reactions. some extra diethyl ether were added, which was followed by stirring (26), 51 (14). To obtain a complete removal of the template, the as-syn-analyses were performed with a Varian Star 3600 gas chromatograph equipped with a flame-ionisation detector and a Chrompack thesised zeolite was subjected to three subsequent calcination steps.…”