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Accelerated and Enantioselective Synthesis of a Library of P‐Stereogenic Urea Phosphines
Author(s) -
Koshti Vijay S.,
Gote Ravindra P.,
Chikkali Samir H.
Publication year - 2018
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/ejoc.201801309
Subject(s) - stereocenter , chemistry , urea , enantioselective synthesis , catalysis , enantiomer , phosphorus , medicinal chemistry , stereochemistry , organic chemistry
Chiral phosphorus ligands play a central role in majority of the asymmetric transformations. However, access to chiral phosphorus ligands is limited due to their challenging synthesis. Reported here is a highly efficient and accelerated catalytic asymmetric synthesis of P‐stereogenic urea containing phosphines leading to a small library of 18 chiral phosphorus compounds. Characteristic two doublets in a 31 P NMR spectrum, spectroscopic and analytical evidences authenticated the formation of [Pd‐{( S , S ) Me‐FerroLANE}( m ‐phenylurea)( I )] complex. Indeed, [Pd‐{( S , S ) Me‐FerroLANE}( m ‐phenylurea)( I )] was found to catalyze the C‐P coupling reaction and quantitative conversion was observed within 18 hours. Under optimized conditions, iodophenyl urea's ( 2a – 2j ) were treated with secondary phosphines ( 1a – 1c ) in presence of [Pd‐{( S , S ) Me‐FerroLANE}( m ‐phenylurea)( I )] to obtain P‐stereogenic urea phosphines 5a – 5r . The identity of these urea derived phosphines was unambiguously ascertained using a combination of spectroscopic and analytical methods. The catalyst tolerated various functional groups and yielded corresponding urea containing phosphines with an enantiomeric excess in the range of 15–62 %.