Cyclopropenones in the synthesis of indolizidine, pyrrolo[2,1-a]isoquinoline and indolizino[8,7-b]indole alkaloids

Abstract

Cyclopropenones in the synthesis of indolizidine, pyrrolo[2,1-a]isoquinoline and indolizino[8,7-b]indole alkaloids

Transition-Metal-, Additive-, and Solvent-Free [3 + 3] Annulation of RCF2-Imidoyl Sulfoxonium Ylides with Cyclopropenones to Give Multifunctionalized CF3-Pyridones

“…In addition, a low yield (23%) was observed when Ph-imidoyl sulfoxonium ylide was used as substrate. This result documented the importance of the electron-deficient groups attached to the imidoyl sulfoxonium ylides ( 3z ) . Finally, N -alkyl TFISY could also deliver the desired product in 97% yield ( 3A ).…”

“…It is reasonable to consider that TFISY would be in equilibrium with intermediate I at elevated temperature. Subsequently, nucleophilic addition of intermediate I with cyclopropenone 2 generates the cyclopropene intermediate II . The ring-opening process of the highly strained cyclopropene intermediate II occurred to give intermediate III .…”

Synthesis of legonmycins A and B, C(7a)-hydroxylated bacterial pyrrolizidines

“…Taken together, it seems reasonable to envisage that ready equilibration of the pyrrolizixenamide enantiomers (and those of related molecules such as jenamidine A and the prelegonmycins) via the hydroxypyrrole tautomer, and aerial oxidation of this electron-rich intermediate, would offer a non-enzymatic route to the various C(7a)-hydroxylated bacterial pyrrolizidines including the legonmycins, jenamidines B and C, and bohemamine D (cf. [ 26 – 30 ]).…”

Synthetic Strategies for the Construction of Indolizines and Indolizine‐fused Compounds: Thienoindolizines and Indolizinoindoles

“…[93] Around the same time, Hemming's group considered this reaction to obtain the corresponding derivatives of indolizinoindoles 275 m-o, which were obtained in 74-81 % yield (Scheme 81). [94] In a study of the Favi's group, indolizino[8,7-b]indole derivatives 277 were synthesized via intramolecular dearomatic cyclization of indole-linked pyrroles 276 stimulated by TFA (Scheme 82). [95] Cui's group continued the investigation and broadened the scope.…”