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Enantioselective Total Syntheses of (–)‐Isonitramine, (–)‐Sibirine, and (+)‐Nitramine by Ring‐Closing Metathesis
Author(s) -
Pandey Ganesh,
Prasanna Kumara C.,
Kumar Burugu Shiva,
Puranik Vedavati G.
Publication year - 2011
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.201101256
Subject(s) - enantioselective synthesis , chemistry , metathesis , ring closing metathesis , total synthesis , stereochemistry , yield (engineering) , ring (chemistry) , salt metathesis reaction , organic chemistry , catalysis , materials science , metallurgy , polymerization , polymer
Concise enantioselective total syntheses of naturally occurring 2‐azaspiro[5,5]undecan‐7‐ol ( Nitraria ) alkaloids viz. (–)‐isonitramine, (–)‐sibirine, and (+)‐nitramine are accomplished in 42, 38, and 25 % overall yield, respectively, in six steps starting from enantiomerically pure ( S )‐methyl 3‐allyl‐2‐oxo‐1,2,3,6‐tetrahydropyridine‐3‐carboxylate (>99 % ee ). The key feature of the syntheses involves diastereoselective Hosomi–Sakurai allylation followed by ring‐closing metathesis.