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Stereoselective total syntheses of (±)‐chanoclavine I and (±)‐isochanoclavine I by an intramolecular nitrone‐olefin/cycloaddition . Preliminary communication
Author(s) -
Oppolzer Wolfgang,
Grayson J. Ian
Publication year - 1980
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19800630639
Subject(s) - chemistry , nitrone , intramolecular force , stereoselectivity , cycloaddition , olefin fiber , stereochemistry , total synthesis , indole test , organic chemistry , catalysis
The racemic alkaloids chanoclavine I ( 1 ) and isochanoclavine I ( 2 ) have been synthesized stereoselectively from indole‐4‐carbaldehyde ( 3 ) by a sequence of 11 operations in overall yields of 14% and 2.4%, respectively. The key step 6 → 8 (Scheme 2) involves a transient nitrone 7 which undergoes a regio‐ and stereoselective intramolecular cycloaddition to a 1,2‐disubstituted olefinic bond.