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Iron‐Catalyzed Oxidative Mono‐ and Bis‐Phosphonation of N , N ‐Dialkylanilines
Author(s) -
Han Wei,
Mayer Peter,
Ofial Armin R.
Publication year - 2010
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/adsc.201000092
Subject(s) - chemistry , benzophenone , catalysis , medicinal chemistry , phosphonate , yield (engineering) , ring (chemistry) , iron(iii) chloride , chloride , organic chemistry , materials science , metallurgy
Abstract The dehydrogenative α‐phosphonation of substituted N , N ‐dialkylanilines by dialkyl H ‐phosphonates was achieved under mild conditions by using environmentally benign iron(II) chloride as catalyst and tert ‐butyl hydroperoxide as oxidant. The reaction proceeded in the presence of electron‐donating (methoxy, methyl, benzyl) and electron‐withdrawing ring‐substitutents (bromo, carbonyl, carboxyl, m ‐nitro) in moderate to good yields. The X‐ray crystal structure of N ‐(5,5‐dimethyl‐2‐oxo‐2λ 5 ‐[1,3,2]dioxaphosphinan‐2‐yl‐methyl)‐ N ‐methyl‐ p ‐toluidine was determined. Bis‐(4‐(dimethylamino)phenyl)methane and bis‐4,4′‐(dimethylamino)benzophenone underwent bisphosphonation selectively by respective monophosphonation at the remote dimethylamino groups. Furthermore, the use of excess dialkyl H ‐phosphonate and oxidant allowed us to functionalize both methyl groups of N(CH 3 ) 2 in N , N ‐dimethyl‐ p ‐toluidine and N , N ‐dimethylaminomesidine, respectively, to obtain α,α′‐bisphosphonatoamines in high yield.