Cobalt‐Catalyzed Reductive Dimethylcyclopropanation of 1,3‐Dienes

Abstract

Dimethylcyclopropanes are valuable synthetic targets that are challenging to access in high yield using Zn carbenoid reagents. Herein, we describe a cobalt-catalyzed variant of the Simmons-Smith reaction that enables the efficient dimethylcyclopropanation of 1,3-dienes using a Me CCl /Zn reagent mixture. The reactions proceed with high regioselectivity based on the substitution pattern of the 1,3-diene. The products are vinylcyclopropanes, which serve as substrates for transition-metal-catalyzed ring-opening reactions, including 1,3-rearrangement and [5+2] cycloaddition. Preliminary studies indicate that moderately activated monoalkenes are also amenable to dimethylcyclopropanation under the conditions of cobalt catalysis.

Dreyfus‐Preis und Camille‐Dreyfus‐Teacher‐Scholar‐Preise 2019

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Christopher Uyeda (Purdue University) studierte an der Columbia University, New York, und promovierte 2011 unter Anleitung von Eric N. Jacobsen an der Harvard University. Nach einem Postdoktorat in der Gruppe von Jonas Peters am California Institute of Technology, Pasadena, begann er 2013 als Assistant Professor im Department of Chemistry der Purdue University mit eigener Forschung.…”

“…Uyedas Gruppe entwirft Übergangsmetallkatalysatoren, die Metall‐Metall‐Bindungen als aktive Zentren enthalten, für die Umwandlung ungewöhnlicher Zwischenstufen wie Vinylidene. In einer Zuschrift in der Angewandten Chemie beschrieben sie eine cobaltkatalysierte reduktive Dimethylcyclopropanierung von 1,3‐Dienen …”

Dreyfus Prize and Camille Dreyfus Teacher‐Scholar Awards 2019

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Christopher Uyeda (Purdue University) studied at Columbia University, New York, and earned his PhD for work with Eric N. Jacobsen at Harvard University in 2011. Subsequently, he was a postdoctoral fellow at California Institute of Technology, Pasadena, in the group of Jonas Peters until, in 2013, he started his independent research as an Assistant Professor in the Department of Chemistry of Purdue University.…”

“…Uyeda's group designs transition‐metal catalysts with metal–metal bonds as active sites for transformations of unusual reactive intermediates such as vinylidenes. In a Communication in Angewandte Chemie , they described a cobalt‐catalyzed reductive dimethylcyclopropanation of 1,3‐dienes …”

Carbene reactivity from alkyl and aryl aldehydes

“…In a complementary approach, Simmons-Smith cyclopropanations by Zn carbenoids (from gem-dihalides) enable incorporation of the smallest divalent carbon, CH 2 (14,15). However, a protons are rarely tolerated owing to 1,2-H migration of the Zn carbenoid (16). Despite elegant solutions for Matteson rearrangement by Li-boronate carbenoids (17)(18)(19)(20), Mo-mediated ketone deoxygenation (21,22), and Au-catalyzed alkyne cyclizations (23,24), there remains no general approach to access nonstabilized alkyl carbenes or for their use in the wide range of carbene reactivity available to stabilized diazo reagents (25).…”