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Zirconium‐Catalyzed Intermolecular Hydroamination of Alkynes with Primary Amines
Author(s) -
Born Karolin,
Doye Sven
Publication year - 2012
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.201101298
Subject(s) - hydroamination , chemistry , steric effects , sulfonamide , regioselectivity , catalysis , amine gas treating , primary (astronomy) , intermolecular force , benzylamine , organic chemistry , medicinal chemistry , combinatorial chemistry , molecule , physics , astronomy
A simple catalyst system generated in situ by combination of 5 mol‐% [Zr(NMe 2 ) 4 ] and 10 mol‐% of a sulfonamide catalyzes the intermolecular hydroamination of alkynes with primary amines. At elevated temperatures, hydroamination is achieved with both internal and terminal alkynes as well as with sterically demanding and less demanding primary amines. In contrast, secondary amines do not react under identical conditions. Of the sulfonamide additives investigated, sterically demanding tosylamides such as N ‐( tert ‐butyl)‐ p ‐toluenesulfonamide give the best results. The regioselectivity of the addition of amine to unsymmetrically substituted internal as well as terminal alkynes is significantly influenced by the nature of the sulfonamide additive. In particular, the successful use of sterically less demanding primary amines such as n ‐hexyl‐ or benzylamine clearly indicates that the assumption that Zr catalysts generally form catalytically inactive bridging μ 2 ‐imido dimers or other unreactive intermediates in the presence of these amines is not correct.