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Synthesis of a Quaternary N , N′ ‐Aminal‐Containing A–E Ring System of Palau′amine via an Enamide‐Type Overman Rearrangement Reaction
Author(s) -
Imaoka Takuya,
Iwata Makoto,
Nagasawa Kazuo
Publication year - 2018
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201800086
Subject(s) - aminal , chemistry , stereochemistry , imidazole , ring (chemistry) , dabco , curtius rearrangement , rearrangement reaction , pericyclic reaction , bicyclic molecule , ketone , stereoselectivity , pyrrole , cascade reaction , sigmatropic reaction , octane , medicinal chemistry , organic chemistry , catalysis
We present a synthesis of the pentacyclic A–E ring system of palau′amine, a member of the dimeric pyrrole‐imidazole alkaloid (PIA) family. The synthesis features tandem elimination–Michael addition reaction to obtain cis ‐fused bicyclo[3,3,0]octane, followed by stereoselective ketone reduction, and further elaboration to obtain the tetracyclic precursor for the Overman rearrangement reaction. The enamide‐type Overman rearrangement reaction generated the N , N′ ‐aminal quaternary asymmetric center at C10, and ring closure provided the desired pentacycle.