Exploring Acetylene Chemistry: A Transition Metal-Free Route to Dienyl 6,8-Dioxabicyclo[3.2.1]octanes from Ketones and Acetylenes

Elena Y Schmidt; Inna V Tatarinova; Nadezhda V Semenova; Nadezhda I Protsuk; Igor' A Ushakov; Boris A Trofimov

doi:10.1021/acs.joc.8b01449

Exploring Acetylene Chemistry: A Transition Metal-Free Route to Dienyl 6,8-Dioxabicyclo[3.2.1]octanes from Ketones and Acetylenes

J Org Chem. 2018 Sep 7;83(17):10272-10280. doi: 10.1021/acs.joc.8b01449. Epub 2018 Jul 30.

Authors

Elena Y Schmidt¹, Inna V Tatarinova¹, Nadezhda V Semenova¹, Nadezhda I Protsuk¹, Igor' A Ushakov¹, Boris A Trofimov¹

Affiliation

¹ A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch , Russian Academy of Sciences , 1 Favorsky Street , 664033 Irkutsk , Russia.

PMID: 30025454
DOI: 10.1021/acs.joc.8b01449

Abstract

Dienyl derivatives of 6,8-dioxabicyclo[3.2.1]octanes, closely related to naturally abundant molecules, have been synthesized from 2-acetyl-3,4-dihydropyrans (readily available from ketones and acetylene in two steps), which further add to aryl(hetaryl)acetylenes in the KOBu^t/DMSO superbase system (105 °C, 1.5 h) to stereoselectively give the corresponding E-styryl adducts. The latter undergo ring closure (NH₄Cl/H₂O, acetonitrile, reflux, 8 h) to form the 6,8-dioxabicyclo[3.2.1]octane core decorated with the (1 Z,3 E)-diene substituent.