A De Novo Approach for the Atroposelective Synthesis of C5 Aryl Pyrazoles via 5-endo-dig Cyclization
Bhuvnesh Singh1, Shreya Tewari1, Ravi P Singh1
1Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
Abstract:
Herein we present a chiral silver phosphate-catalyzed 5-endo-dig nucleophilic cyclization of alkynyl β-alkoxy naphthalene-substituted hydrazones under mild conditions, leading to the synthesis of various C-C axially chiral pyrazoles in excellent yields and enantioselectivities. While the silver salt accelerates the desired transformation, the chiral phosphoric acid plays a key role in inducing enantioselectivity. Moreover, this work also explores the synthetic applications and conformational stability of the obtained product.
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