A Convenient and Stereoselective Synthesis of (E)-Vinylseleno Zirconocenes and (E)-Vinylic Selenol Esters

Abstract

The insertion of elemental selenium into the Csp 2 -Zr bond of alkenylchlorozirconocenes affords (E)-vinylseleno zirconocenes, which were trapped by acyl chlorides giving (E)-vinylic selenol esters in good yields.

Atom Efficient Preparation of Zinc Selenates for the Synthesis of Selenol Esters under “On Water” Conditions

“…: 39°–40 °C (Lit. : [38] 37°–38 °C). 1 H-NMR (CDCl 3 , ppm) δ: 7.96–7.92 (m, 2H, H-Ar), 7.63–7.42 (m, 8H, H-Ar) ppm.…”

“…As a consequence of the increasing demand for selenol esters, the number of methods to prepare this class of compounds has been increased along the years [1,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43] Among the strategies to prepare selenol esters there are the reactions of nucleophilic selenium reagents with an acyl group source, such as N -acyl benzotriazoles [17,18] activated carboxylic acids (using DCC [3] or PBu 3 [4,5,19,20]), enol esters [21], anhydrides [22,23,24], esters [25], carbon monoxide [26,27], aldehydes [28,29] or acyl chlorides [2,7,30,31,32,33,34,35,36,37,38,39,40,41,42,43]. Other approaches to selenol esters involve the alkylation of selenocarboxylate anions with alkyl h...…”

“…The acyl substitution of acyl chlorides is by far the most explored method to access selenol esters, mainly because of its versatility, since the diversity of acyl chlorides that can be prepared is practically endless. The pivotal step in this reaction is the generation of the nucleophilic selenium species and a range of reagents have been used for this purpose, including Se°/ArMgBr [2], (NH 2 ) 2 C=Se/Et 3 N [30], Se°/NaBH 4 [6], InI/(PhSe) 2 [31,39,40], Se°/LiAlH 4 [32,37], (RSe) 2 /Zn/AlCl 3 [33], Ph(NH 2 )C=Se [34], (Bu 3 Sn) 2 /(PhSe) 2 /hv [35,36], Se°/R 2 C=CZrCp 2 Cl [38], (RSe) 2 /Zn°/[bmim]PF 6 [41], (PhSe) 2 /Hg°/dioxane [42] and (PhSe) 2 /SnCl 2 /CuBr 2 /[bmim]BF 4 [43]. Despite these reaction systems afforded a range of selenol esters, they suffer from one or more of the following drawbacks: use of VOCs as solvent, strong bases, strong and moisture sensible reducing agents, expensive reagents and low atom-economy.…”

Applications of stoichiometric transition metal complexes in organic synthesis

“…4 This 1,1-bimetalloalkene can then be quenched with tin, selenium or tellurium halides. Huang has reported similar procedures to produce vinyl sulfones, 5 vinyl selenol esters, 6 vinyl phosphonates, 7 and vinyl sulfides. 8 A good illustration of this methodology in synthesis is the preparation of enynes by reaction of alkynes with Schwartz's reagent to produce the functionalised alkene, followed by coupling of this with an alkynyl iodonium tosylate to produce the enyne (Scheme 2).…”

A Stereoselective Synthesis of (E)-Arylvinyl Selenides via Coupling of (E)-Vinylseleno Zirconocenes and Diaryliodonium Salts

“…This method has been applied to the stereoselective synthesis of vinylseleno esters. 2 Herein we report a stereoselective synthesis of (E)-arylvinyl selenides via coupling of (E)-vinylseleno zirconocenes 1 and diaryliodonium salts (Scheme 1). The insertion of elemental selenium into the C(sp 2 )^Zr bond proceeds smoothly in THF at room temperature and is usually completed within 30 minutes, a¡ording a red solution.…”