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Cyclometallated Gold(III) Complexes as Effective Catalysts for Synthesis of Propargylic Amines, Chiral Allenes and Isoxazoles
Author(s) -
Kung Karen KaYan,
Lo Vanessa KarYan,
Ko HokMing,
Li GaiLi,
Chan PuiYing,
Leung KingChi,
Zhou Zhongyuan,
Wang MingZhong,
Che ChiMing,
Wong ManKin
Publication year - 2013
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.201300005
Subject(s) - chemistry , allene , catalysis , amine gas treating , ring (chemistry) , racemization , medicinal chemistry , aldehyde , combinatorial chemistry , organic chemistry , stereochemistry
A series of cyclometallated gold(III) complexes [Au( $\widehat{CN}$ )Cl 2 ] 1a – l (H $\widehat{CN}$ =arylpyridines) and a PEG‐linked complex 1m were synthesized. Complexes 1a – m are effective in catalyzing the synthesis of propargylic amines, chiral allenes and isoxazoles. Six‐membered ring cyclometallated gold(III) complexes 1f – l exhibited higher catalytic activity than five‐membered ring cyclometallated gold(III) complexes 1a – e . The diastereoselectivity of propargylic amines could be tuned by using chiral aldehyde and/or amine substrates. Excellent enantioselectivities (90–98% ee ) were achieved in chiral allene synthesis. Chiral allene racemization could be minimized by using 1f as catalyst. The PEG‐linked catalyst 1m is the most catalytically active towards synthesis of propargylic amines, in which case a product turnover of 900 was achieved. Moreover, 1m could be repeatedly used for 12 reaction cycles, leading to an overall turnover number of 872.