Neat total synthesis of six monoterpenic alkaloids of the actinidine series
摘要:
A concise enantiopure synthesis of six monoterpenic alkaloids of the actinidine series possessing a cyclopenta[c]lpyridine skeleton, (+)-deoxyrhexifoline (4), (+)-boschniakinic acid (5), (+)-boschniakine (6), (-)-plantagonine (7), (-)-indicaine (8) and (-)-tecostidine (9) is reported starting with the chiral precursor 3 -bromo-5 - ((4R)-phenyloxazolin-2-yl)pyridine (10). It involves a C-4 regioselective connection of a butene appendice and an intramolecular 5-exo-trig Heck annulation sequence followed by hydrogenation of the exocyclic alkene. Mixture of (3R)- and (3S)-7-((4R)-phenyloxazolin-2-yl)cyclopenta[clpyridines was separated by HPLC before being transformed into enantiopure natural products (4-9) by modification of the oxazoline group. (C) 2007 Elsevier Ltd. All rights reserved.
A concise enantiopure synthesis of six monoterpenic alkaloids of the actinidine series possessing a cyclopenta[c]lpyridine skeleton, (+)-deoxyrhexifoline (4), (+)-boschniakinic acid (5), (+)-boschniakine (6), (-)-plantagonine (7), (-)-indicaine (8) and (-)-tecostidine (9) is reported starting with the chiral precursor 3 -bromo-5 - ((4R)-phenyloxazolin-2-yl)pyridine (10). It involves a C-4 regioselective connection of a butene appendice and an intramolecular 5-exo-trig Heck annulation sequence followed by hydrogenation of the exocyclic alkene. Mixture of (3R)- and (3S)-7-((4R)-phenyloxazolin-2-yl)cyclopenta[clpyridines was separated by HPLC before being transformed into enantiopure natural products (4-9) by modification of the oxazoline group. (C) 2007 Elsevier Ltd. All rights reserved.
Danilowa, Zhurnal Obshchei Khimii, 1956, vol. 26, p. 2069; engl. Ausg. S. 2307