Recent advances in the synthesis of cyclic sulfinic acid derivatives (sultines and cyclic sulfinamides)

Abstract

The chemistry of cyclic sulphinic acid derivatives (sultines and cyclic sulfinamides) long remains less developed due to their inaccessibility. Considering the importance of cyclic sulfinate esters and amides in the...

Energy-Transfer-Powered Sultine Synthesis

“…Delightfully, δ-sultines 4 and 5 were obtained in 90 and 64% yield, respectively, which are challenging-to-access with established means. 1,8 Primary 6a− 10a, secondary 11a−13a, and tertiary 14a alkyl-substituted substrates were all successfully employed in this process, delivering the desired products 6−14 in moderate-to-good yields. A variety of carboxylate-tethered sulfinates derived from alcohols were all suitable substrates under the current reaction conditions, giving the sultines 15−20 in good yields with moderate dr values.…”

“…As summarized in Scheme , this EnT-powered cyclization reaction occurred efficiently with various terminal alkenyl sulfinate substrate 1 , leading to the corresponding γ/δ-sultines 2 – 40 with one cyclic quaternary center in good-to-excellent yields. Delightfully, δ-sultines 4 and 5 were obtained in 90 and 64% yield, respectively, which are challenging-to-access with established means. , Primary 6a – 10a , secondary 11a – 13a , and tertiary 14a alkyl-substituted substrates were all successfully employed in this process, delivering the desired products 6 – 14 in moderate-to-good yields. A variety of carboxylate-tethered sulfinates derived from alcohols were all suitable substrates under the current reaction conditions, giving the sultines 15 – 20 in good yields with moderate dr values.…”

“…Sulfur-containing heterocycles, especially the sultines and sultones (sulfur-containing analogues of lactones), play a pivotal role in the pharmaceutical, agrochemical, materials, and petrochemical industries and are prominent structural motifs that can be found in many natural products and bioactive molecules (Figure a). – The selective installation of functional groups with different substitution patterns at a specific position over sultine cores is of significant interest in synthetic and medicinal chemistry. However, the synthesis of such molecular scaffolds remains extremely challenging, only very limited protocols have been developed to date, and most of them suffer from harsh conditions and low efficiency, – which severely obstructs the application potential of sultines. To this end, the development of new methods for the atom-economical construction of this skeleton is highly desirable, especially for those with different ring sizes and substitution patterns.…”

“…The development of new synthetic methods is considered one of the most important areas of chemical research, as access to organic molecules is the basis for many applied sciences such as medicinal chemistry and materials science. Recently, remarkably progress has been achieved to build structurally diverse cyclic sulfinates that long remained little explored, as elegantly established by Fensterbank, Maestro, Bray, Welker, and Fallis. ,,, For example, dehalogenation cyclization represents a highly enabling strategy for remote radical initiators (such as Bu 3 SnH, AIBN) or TTMMSS combined with harsh conditions (typically T > 100 °C) limits the broad applicability (Figure b) . More recently, the Shu group demonstrated an efficient procedure for the facile synthesis of functionalized γ-sultines through a radical-polar cyclization process, however, only 3,3-disubstituted γ-sultines were formed with the leaving group (LG) as waste (Figure c) .…”

Thermoinduced Radical Cyclization for the Synthesis of Sultines

“…Sultines, the sulfur analogues of lactones, were first reported as far back as 1893 by a dehydration reaction of a sulfinic acid and an alcohol and constitute a fascinating class of S-heterocyclic compounds whose chemistry continues to be of interest in view of their unique structural characteristics. However, the chemistry of the sultines has not yet been adequately studied for a long time due to the lack of efficient synthesis methods. , Until recently, a few attractive methods were discovered for the installation of these S-heterocycle skeletons based on photo- or thermo- induced radical chemistry …”