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Stereoselective Alkylations of Enolates Derived from Ligands Attached to the Indenyl Iron Chiral Auxiliary [(η 5 ‐C 9 H 7 )Fe(CO)(PPh 3 )]: X‐ray Crystal Structure and Conformational Analysis of [(η 5 ‐C 9 H 7 )Fe(CO)(PPh 3 )COCH 3 ]
Author(s) -
Davies Stephen G.,
Sarah Holland K.,
Sutton Kevin H.,
Mcnally John P.
Publication year - 1991
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.199100004
Subject(s) - chemistry , deprotonation , alkylation , stereoselectivity , diastereomer , cyclopentadienyl complex , stereochemistry , aldol reaction , crystallography , organic chemistry , catalysis , ion
The preparation, X‐ray crystal structure, and conformational analysis of the acetyl complex [(η 5 ‐ C 9 H 7 )Fe(CO)(PPh 3 )COCH 3 ] ( 5 ) are described. Deprotonation and alkylation of complex 5 generates the corresponding propanoyl ( 6 ) and butanoyl ( 7 ) complexes. Deprotonation and alkylation of complexes 6 and 7 to generate complementary diastereoisomers of the corresponding 2‐methylbutanoyl complex occur with high stereoselectivities. The aldol reaction of the diethylaluminium enolate derived from 5 with acetaldehyde also shows a high stereoselectivity (95:5). The reactions of the indenyl complex 5 clearly parallel those for the cyclopentadienyl analogue and this is rationalised in terms of the conformational analysis.