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Regioselective Amine–Borane Cyclization: Towards the Synthesis of 1,2‐BN‐3‐Cyclohexene by Copper‐Assisted Triazole/Gold Catalysis
Author(s) -
Motika Stephen E.,
Wang Qiaoyi,
Akhmedov Novruz G.,
Wojtas Lukasz,
Shi Xiaodong
Publication year - 2016
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201604986
Subject(s) - hydroboration , chemistry , borane , alkyne , amine gas treating , catalysis , regioselectivity , combinatorial chemistry , triazole , medicinal chemistry , organic chemistry , polymer chemistry
The combination of triazole/gold (TA‐Au) and Cu(OTf) 2 is identified as the optimal catalytic system for promoting intramolecular hydroboration for the synthesis of a six‐membered cyclic amine–borane. Excellent yields (up to 95 %) and regioselectivities (5‐exo vs. 6‐endo) were achieved through catalyst control and sequential dilution. Good functional‐group tolerance was attained, thus allowing the preparation of highly functionalized cyclic amine–borane substrates, which could not be achieved using other methods. Deuterium‐labeling studies support the involvement of a hydride addition to a gold‐activated alkyne with subsequent C−B bond formation.