Metal Complex‐Controlled Regio‐, Diastero‐ and Enantioselective 1,3‐Dipolar Cycloaddition of Azomethine Ylides with Benzo[b]thiophene Sulfones

Abstract

The Cu(MeCN) PF /DTBM-Segphos complex catalyzed the highly diastereo- and enantioselective 1,3-dipolar cycloaddition of azomethine ylides with benzo[b]thiophene sulfones with the usual regiochemistry to give single isomers of the exo-cycloadducts in good yields. In contrast, the AgOAc/ThioClickFerrophos complex catalyzed the reaction with atypical regiochemistry to give the endo-cycloadducts as major products with excellent enantioselectivities. Thus, the choice of chiral metal complex enabled the regio- and stereoselective synthesis of chiral fused sulfolanes.

Advances in Synthesis of Enantioenriched Chiral Sulfones by Enantioselective Conjugate Addition Reactions

“…In 2017 Fukuzawa et al reported a highly regio-and diastereoselective 1,3-dipolar cycloaddition for obtaining chiral sulfolanes by using Cu(MeCN) 4 PF 6 /DTBM-Segphos 199 or AgOAc/ThioClickFerrophos 200 complex catalyzed (Scheme 52). [71] In these catalytic systems, the reaction catalyzed by Cu(MeCN) 4 PF 6 /DTBM-Segphos 199 complex led to the formation of exo-cycloadducts 201 with high enantioselectivity. Interestingly, when using AgOAc/ThioClickFerrophos 200 complex as catalyst, an unusual regiochemistry could be found and the endo-cycloadducts 202 with high enantioselectivity was provided as the main product.…”

The Crucial Role of S‐oxidation State on the Selectivity and Reaction Rate of the 1,3‐Dipolar Cycloaddition of Azomethine Ylides and Homochiral Thiazolines

“…[22] The reaction between azomethine ylides and sulfinyl or sulfonyl groups has been reported in the past, with diverse results. [23][24][25][26][27][28][29][30] Among those references, it is interesting to mention two publications in which different strategies were developed starting from 1,2 diactivated sulfonyl acrylates to obtain exo adducts with a regiochemistry controlled by the sulfonyl group [30] or endo adducts with the opposite regiochemistry, so controlled by the ester moiety. [26] The origin of these switch on diastereo-and regioselectivity relies on the use of a copper or silver catalyst, respectively, and different ligands.…”

Synthesis of non-racemic 4-nitro-2-sulfonylbutan-1-ones via Ni(II)-catalyzed asymmetric Michael reaction of β-ketosulfones

“…Therefore, the development of methods for the asymmetric synthesis of polyfunctional sulfones is valuable. The most notable of them are Ag- and Cu-catalyzed 1,3-dipolar cycloaddition reactions, which allows to obtain chiral cyclic sulfones with high enantioselectivity [10–12]. Also non-racemic cyclic sulfones can be obtained by the Diels–Alder reaction, catalyzed by chiral Lewis acids or organocatalysts.…”