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Facile Synthesis of 7‐Dimethylamino‐ endo ‐tricyclo[5.2.2.0 1,6 ]undec‐10‐en‐9‐ones
Author(s) -
Wu YaoTing,
Schirmer Heiko,
Noltemeyer Mathias,
de Meijere Armin
Publication year - 2001
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 - 10.1002/1099-0690(200107)2001:13<2501::aid-ejoc2501>3.0.co;2-o
Subject(s) - chemistry , alkyne , cyclopentadiene , carbene , medicinal chemistry , cyclohexane , pyridine , hydrolysis , stereochemistry , organic chemistry , catalysis
Pentacarbonyl[(2 E )‐3‐cyclohexenyl‐3‐dimethylamino‐1‐ethoxy‐2‐propen‐1‐ylidene]chromium ( 2 ) yields 7‐dimethylamino‐ endo ‐tricyclo[5.2.2.0 1,6 ]undec‐10‐en‐9‐ones 5 (15−88%, 12 examples) upon treatment with alkynes 3 in pyridine, most probably by a 6π‐electrocyclization followed by a subsequent reductive elimination/intermolecular Diels−Alder reaction with the alkyne and eventual hydrolysis. The direct cyclization of 2 to the cyclohexane‐annelated cyclopentadiene 6 is faster than the usual alkyne insertion of α,β‐unsaturated Fischer carbene complexes. The [4+2] cycloadditions of 7 and the added alkynes 3 occur with high degrees of regio‐ and complete diastereoselectivity.