Synthesis of Disubstituted Dithioethers: tert-Butoxide Promoted Elimination/Ring Opening of 1,3-Dithianes Followed by Palladium-Catalyzed C–S Bond Formation

Abstract

We report the tandem base-promoted elimination/ring-opening of 2-benzyl-1,3-dithianes with subsequent cross coupling of the pendent thiol with a range of aryl bromides. A simple Pd(OAc)2/Xantphos catalyst system affects this new reaction and is compatible with a wide range of functional groups, including heteroaromatic coupling partners. The transformation proceeds in good to excellent yields (69-99%) and exhibits strong stereoselectivity, forming the E-alkene as the major diastereomer. This new methodology provides access to nonsymmetric propylene styryl/aryl dithioethers, a previously undisclosed motif.

Cyclopentyl Methyl Ether: An Elective Ecofriendly Ethereal Solvent in Classical and Modern Organic Chemistry

“…[45] By replacing the 2-aryl-1,3-dithianes with benzyl-type dithianes, new reactivity pathways paved on CÀSb ond-formatione vents can be similarly activated in CPME. [46] The versatility of Pd-catalyzed chemistry in CPME is also showcased in additional studies dealingw ith arylation processesa tp ositions adjacentt oa midic carbon atoms, [47] benzylp hosphonates, [48] benzylic phosphine oxides, [49] a-phosphonoacetates, [50] and cyclopropyln itriles [51] under (almost) analogous conditions. Doucet and Beydoun have developeda ne conomically viable and environmentally attractive process in which CPME promotes the palladium-catalyzed direct arylation of heteroaromatics.…”

“…Schmink discloses the development of a method for the Pd‐catalyzed cross‐coupling of 2‐aryl‐1,3‐dithianes, from which the products can be further derivatized into ketones or diarylmethanes (Scheme e) . By replacing the 2‐aryl‐1,3‐dithianes with benzyl‐type dithianes, new reactivity pathways paved on C−S bond‐formation events can be similarly activated in CPME . The versatility of Pd‐catalyzed chemistry in CPME is also showcased in additional studies dealing with arylation processes at positions adjacent to amidic carbon atoms, benzyl phosphonates, benzylic phosphine oxides, α‐phosphonoacetates, and cyclopropyl nitriles under (almost) analogous conditions.…”

Base dependent 1,3-dithioacetals rearrangement over sulfoxidation under visible-light photocatalysis to access disulfide-linked-dithioesters

“…Schmink and coworkers demonstrated synthesis of dithioether via the selective cleavage of C-S bond of thioacetals in the absence of oxidizing reagent however at an elevated temperature using metal catalyst Pd(OAc)2. 18 However this protocol was limited to thioacetals containing benzylic β-hydrogen to sulfur atom of thioacetals. The efforts to cleave the single C-S bond of thioacetal selectively have led to interesting and different products (Scheme 1).…”

Enhanced catalytic activity of oxovanadium complexes in oxidative polymerization of diphenyl disulfide

“…6 Recently, as represented by copper acetate-dimethyl sulfoxide (DMSO) promoted methylthiolation of arenes, 7 β-hydroxysulfide synthesis via air oxidative hydroxysulfurization 8 and dithioether synthesis from 1,3-dithianes via ring-opening and palladium catalyzed C-S bond formation have been reported. 9 Sulfur chemistry is thus one of the hot topics in current organic chemistry relevant to polymer synthesis. 10 However, catalytic systems to produce the synthetically useful sulfonium electrophiles have been limited to those used in our previous research on the oxygen-oxidative polymerization of diphenyl disulfide catalyzed by VO(acac) 2 .…”