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Palladium‐Titanium Relay Catalysis Enables Switch from Alkoxide‐π‐Allyl to Dienolate Reactivity for Spiro‐Heterocycle Synthesis
Author(s) -
Yang LiCheng,
Tan Zher Yin,
Rong ZiQiang,
Liu Ruoyang,
Wang Yag,
Zhao Yu
Publication year - 2018
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201804160
Subject(s) - umpolung , reactivity (psychology) , palladium , stereocenter , alkoxide , catalysis , chemistry , titanium , combinatorial chemistry , lewis acids and bases , organic chemistry , enantioselective synthesis , nucleophile , medicine , alternative medicine , pathology
Abstract Reported herein is the divergent syntheses of [5,5] and [6,5] spiro‐heterocycles under Lewis‐acid‐assisted palladium catalysis. In particular, an unprecedented switch from alkoxide‐π‐allyl to dienolate reactivity was achieved by the use of palladium‐titanium relay catalysis, and represents umpolung reactivity of vinylethylene carbonates. This method uses a simple procedure and commercially available catalysts, and delivers both classes of spiro‐heterocycles, bearing three contiguous stereocenters, in high yield and uniformly excellent diastereoselectivity.