Synthesis of γ-keto sulfones by copper-catalyzed oxidative sulfonylation of tertiary cyclopropanols

Abstract

Tertiary cyclopropanols undergo ring-opening oxidative sulfonylation to afford γ-keto sulfones when reacting with sulfinate salts in the presence of a copper(ii) acetate catalyst and an oxidant (tert-butyl hydroperoxide or atmospheric oxygen). Various fluoroalkyl, aryl and alkyl sulfinate salts are successfully employed as sulfonylation reagents, affording the corresponding sulfones in up to 94% yields. The experimental protocol is mild and tolerates a number of functionalities in the cyclopropanol substrate. The reaction proceeds via a one-pot oxidation-Michael addition mechanism and can serve as a useful addition to the existing methods for the preparation of γ-keto sulfones based on the sulfa-Michael reaction.

Metal-Catalyzed Transformations of Cyclopropanols via Homoenolates

“…Based on this observation, they achieved Cu-mediated ring-opening β-sulfonylation of cyclopropanols using various sulfinate salts (Scheme 18). 29 The reaction was best achieved using stoichiometric Cu(OAc)2 in combination with TBHP or air as the oxidant. In some cases, the addition of a catalytic amount of Fe(OAc)2 proved beneficial.…”

General Synthesis of Cyclopropanols via Organometallic Addition to 1-Sulfonylcyclopropanols as Cyclopropanone Precursors

“…A: 91% 94 using known copper-mediated conditions, following addition of pmethoxyphenylmagnesium bromide as nucleophile. 32,33 Scheme 5. One-pot sequential addition and homoenolate b-functionalization: cyclopropanone as a 3-carbon linchpin a a All yields correspond to yields of isolated product directly from 1a (0.25 mmol scale).…”

Oxidative radical ring-opening/cyclization of cyclopropane derivatives

“…In the same year, this group developed a similar copper-catalyzed ring-opening and sulfonylation of teriary cyclopropanols 91 with sodium sulfinates 129 for the synthesis of γ-keto sulfones 130 in excellent yields (Scheme 34) [114]. The reaction was compatible with a series of fluoroalkyl, aryl and alkyl sulfinate salts.…”