Premium
Organocatalytic Asymmetric Mannich Cyclization of Hydroxylactams with Acetals: Total Syntheses of (−)‐Epilupinine, (−)‐Tashiromine, and (−)‐Trachelanthamidine
Author(s) -
Koley Dipankar,
Krishna Yarkali,
Srinivas Kyatham,
Khan Afsar Ali,
Kant Ruchir
Publication year - 2014
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201407185
Subject(s) - yield (engineering) , chemistry , acetal , mannich reaction , bicyclic molecule , enantioselective synthesis , organic chemistry , derivative (finance) , stereochemistry , catalysis , materials science , metallurgy , economics , financial economics
An asymmetric, organocatalytic, one‐pot Mannich cyclization between a hydroxylactam and acetal is described to provide fused, bicyclic alkaloids bearing a bridgehead N atom. Both aliphatic and aromatic substrates were used in this transformation to furnish chiral pyrrolizidinone, indolizidinone, and quinolizidinone derivatives in up to 89 % yield and 97 % ee . The total syntheses of (−)‐epilupinine, (−)‐tashiromine, and (−)‐trachelanthamidine also achieved to demonstrate the generality of the process.