American Chemical Society
jo9b01677_si_001.pdf (7.93 MB)

Construction of Complex Bisether-Bridged Medium-Sized Cyclic Compounds from o‑(1-(Acyloxy)propargyl)benzaldehydes under Base and Acid Catalysis

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journal contribution
posted on 2019-08-27, 19:44 authored by Yun-Long Zhao, Ying Cheng
We report herein our serendipitous discovery of the rapid and straightforward accesses to unprecedented diverse complex molecular structures from readily available starting materials. Catalyzed by 1,8-diazabicyclo[5.4.0]­undec-7-ene under mild conditions, o-(1-(acyloxy)­propargyl)­benzaldehydes 1 underwent efficient and selective dimerization reactions to produce novel complex bisether-bridged tricyclic products 3 and 4. The reactions proceeded most probably through dimerizations between 3-methylene-3H-isochromene intermediate and its zwitterionic resonance structures which were generated from a concerted 6-π electrocyclic ring closure reaction from the initially formed (2-formylphenyl)­allene intermediates derived directly from o-(1-(acyloxy)­propargyl)­benzaldehydes. Treatment of the resulting product simply with NaOEt in ethanol and aqueous HCl, respectively, enabled further development of complex molecular diversities.