The synthesis of [9](2,4)pyrrolophanes

Construction of synthetic macrocyclic compounds possessing subheterocyclic rings, specifically pyridine, furan, and thiophene

“…406 This procedure described by Kauffmann should prove to be a very useful route to many novel macrocycles possessing diversified subunits. 463 184, 205, 229, 390), isoxazolophane (ref 205) and pyrrolophanes (ref 176,187,218,445,446).…”

Unsymmetrical Ozonolysis of a Diels−Alder Adduct: Practical Preparation of a Key Intermediate for Heme Total Synthesis

“…The inseparable mixture of 2a and 25a (3.6:1 ratio) was subjected to ketal hydrolysis (Scheme ) in acetone−water with catalytic pyridinium p -toluenesulfonate (PPTS). The resulting keto aldehyde mixture was immediately heated with ammonium carbonate to effect the Paal−Knorr pyrrole synthesis . The resulting crude methyl 2,4-dimethyl-1 H -pyrrole-3-propanoate 26 1b was then formylated at C-2 with trimethyl orthoformate in TFA to afford 3 7 in 39% overall yield from 2a .…”

Selected synthetic strategies to cyclophanes

“…Enyne metathesis: In 1998, Fürstner and co-workers [ 147 ] have employed platinum(II)-catalyzed enyne metathesis as a key step to form cyclophane ring systems which are found in streptorubin B and metacycloprodigiosin [ 148 – 150 ]. In this context, the cyclooctene 164 was reacted with the intermediate formed in situ from chloramine-T and elemental selenium [ 151 ] and yielded the allylic amine derivative 165 (75%).…”