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The Stereoselective Ru 3 (CO) 12 ‐Catalyzed Synthesis of Steroidal 1,3‐Dihydropyrrol‐2‐one Derivatives from α,β‐Unsaturated Imines, Carbon Monoxide and Ethylene
Author(s) -
Imhof Wolfgang,
Berger Daniel,
Kötteritzsch M.,
Rost M.,
Schönecker B.
Publication year - 2001
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/1615-4169(20011231)343:8<795::aid-adsc795>3.0.co;2-m
Subject(s) - chemistry , intramolecular force , moiety , substituent , stereocenter , carbon monoxide , steric effects , ring (chemistry) , stereochemistry , imine , medicinal chemistry , reactivity (psychology) , catalysis , organic chemistry , enantioselective synthesis , medicine , alternative medicine , pathology
The reaction of α,β‐unsaturated imines, derived from steroidal amines and cinnamaldehyde, with carbon monoxide and ethylene leads to the formation of steroids with a 1,3‐dihydropyrrol‐2‐one ring system attached to the D‐ring of the steroid. In addition, a new stereogenic center at C‐3 of the pyrrolone ring is produced during the reaction sequence. In the case of a 16‐position of the imine moiety the yields are nearly quantitative but the diastereoselectivity is low whereas the sterically more hindered 17‐position shows a decreased reactivity but quite good diastereoselectivities. Complete diastereoselectivity is achieved if the starting compound exhibits an additional silyl ether group in the 17β‐position besides the imine subunit in the 16β‐position. The compound bearing the pyrrolone substituent at 17β‐position was characterized by means of X‐ray crystallography showing that the rotation of the pyrrolone ring is hindered by a strongintramolecular hydrogen bond between the carbonyl oxygen of the pyrrolone moiety and the hydrogen at C‐17. The question of whether this intramolecular hydrogen bond is also responsible for the observed diastereoselectivities is discussed.