Intermolecular Pummerer Coupling with Carbon Nucleophiles in Non‐Electrophilic Media

Abstract

A new Pummerer-type C-C coupling protocol is introduced based on turbo-organomagnesium amides, which unlike traditional Pummerer reactions, does not require strong electrophilic activators, engages a broad range of C(sp )-, C(sp )-, and C(sp)-nucleophiles, and seamlessly integrates with C-H and C-X magnesiation. Given the central character of sulfur compounds in organic chemistry, this protocol allows access to unrelated carbonyls, olefins, organometallics, halides, and boronic esters through a single strategy.

Computational and Experimental Study of Turbo‐Organomagnesium Amide Reagents: Cubane Aggregates as Reactive Intermediates in Pummerer Coupling

“…The last step was found to be rate‐determining for both cases, with a calculated barrier of 27.1 kcal mol −1 for complex A and 28.1 kcal mol −1 for complex B . An important observation here is that, in contrast to previous proposals, [16a] the β‐oxide elimination pathway [19] to form a discrete sulfonium intermediate [20] could not be obtained by the calculations (see Supporting Information for details).…”

Sulfur(IV)‐Mediated Unsymmetrical Heterocycle Cross‐Couplings

“…A preliminary survey of nucleophilic heteroaryl reagents indicated a strong preference for Grignard reagents (Figure C, inset). Notably, neither Pummerer rearrangement byproducts nor alkyl deprotonation were observed under the optimized reaction conditions.…”

Mechanism and regioselectivity of the anionic oxidative rearrangement of 1,3-diketones towards all-carbon quaternary carboxylates

“…These fundamental challenges add to the known background reactivity of diketones 4 with H 2 O 2 through rapid de-acylation [6][7][8][9]16,17 and Baeyer-Villiger oxidation. 19,20 In line with our interest in the synthesis of ligands and polar molecules, [21][22][23][24][25][26] we aimed to clarify the mechanism of this reaction and the fundamental role of the various additives reported. We hoped to use this knowledge to understand the complex dynamics of this system and to control the regioselectivity of the alkyl shift in unbiased acyclic substrates.…”