Premium
Stille Cross‐Coupling of a Racemic Planar‐Chiral Ferrocene and Crystallographic Trace Analysis of Catalysis Intermediates and By‐products
Author(s) -
Weber Immo,
Heinemann Frank W.,
Bakatselos Panagiotis,
Zenneck Ulrich
Publication year - 2007
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.200790083
Subject(s) - chemistry , stille reaction , ferrocene , palladium , catalysis , iodobenzene , medicinal chemistry , coupling reaction , polymer chemistry , crystal structure , organic chemistry , electrochemistry , electrode
A pressure‐controlled procedure for the S N 1 reaction of rac ‐1‐[(dimethylamino)methyl]‐2‐(tributylstannyl)ferrocene ( 1 ) to rac ‐1‐(phthalimidomethyl)‐2‐(tributylstannyl)ferrocene ( 2 ) was developed. Pd 0 ‐Catalyzed Stille coupling of 2 with iodobenzene afforded rac ‐1‐phenyl‐2‐( N ‐phthalimidomethyl)ferrocene ( 5 ) in 74% yield; after trace enrichment by crystallization of the combined mother liquors, one single crystal of each, 5 , catalysis intermediate trans‐ iodo( σ ‐phenyl)bis(triphenylarsino)palladium(II) ( 7 ), trans ‐diiodobis(triphenylarsino)palladium(II) ( 8 ), and rac‐ 2,2′‐bis(phthalimidomethyl)‐1,1′‐biferrocene ( 9 ) could be isolated by crystal sorting under a microscope and characterized by X‐ray crystal structure analysis. Furthermore, 5 was deprotected to amine ( 11 ), which does even survive the Birch reduction to rac ‐1‐(aminomethyl)‐2‐(cyclohexa‐2,5‐dienyl)ferrocene ( 12 ).