Premium
Efficient dehydration of primary amides to nitriles catalyzed by phosphorus‐chalcogen chelated iron hydrides
Author(s) -
Li Kai,
Sun Hongjian,
Yang Wenjing,
Wang Yajie,
Xie Shangqing,
Li Xiaoyan,
Fuhr Olaf,
Fenske Dieter
Publication year - 2020
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.5337
Subject(s) - chemistry , catalysis , chalcogen , phosphine , medicinal chemistry , substituent , moiety , chelation , dehydration , stereochemistry , crystallography , inorganic chemistry , organic chemistry , biochemistry
A series of phosphorus‐chalcogen chelated hydrido iron (II) complexes 1–7 , ( o ‐(R' 2 P)‐ p ‐R‐C 6 H 4 Y)FeH (PMe 3 ) 3 ( 1 : R = H, R' = Ph, Y = O; 2 : R = Me, R' = Ph, Y = O; 3 : R = H, R' = i Pr, Y = O; 4 : R = Me, R' = i Pr, Y = O; 5 : R = H, R' = Ph, Y = S; 6 : R = Me, R' = Ph, Y = S; 7 : R = H, R' = Ph, Y = Se), were synthesized. The catalytic performances of 1–7 for dehydration of amides to nitriles were explored by comparing three factors: (1) different chalcogen coordination atoms Y; (2) R' group of the phosphine moiety; (3) R substituent group at the phenyl ring. It is confirmed that 5 with S as coordination atom has the best catalytic activity and 7 with Se as coordination atom has the poorest catalytic activity among complexes 1 , 5 and 7 . Electron‐rich complex 4 is the best catalyst among the seven complexes and the dehydration reaction was completed by using 2 mol% catalyst loading at 60 °C with 24 hr in the presence of (EtO) 3 SiH in THF. Catalyst 4 has good tolerance to many functional groups. Among the seven iron complexes, new complexes 3 and 4 were obtained via the O‐H bond activation of the preligands o ‐ i Pr 2 P(C 6 H 4 )OH and o ‐ i Pr 2 P‐ p ‐Me‐(C 6 H 4 )OH by Fe(PMe 3 ) 4 . Both 3 and 4 were characterized by spectroscopic methods and X‐ray diffraction analysis. The catalytic mechanism was experimentally studied and also proposed.