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Abstract Reactions oftrans‐(C6F5)(p‐tol3P)2Pt(C≡C)nSiEt3(PtC2nSi;n=5, 7, 9) and excessPtClin the presence of wetn‐Bu4N+F−(to effect protodesilylation) under Sonogashira‐type conditions (CuCl, base, other additives) afford the title compoundsPtC10Pt,PtC14Pt, andPtC18Ptin 42–32 % yields. A four‐fold substitution of the phosphine ligands inPtC10Ptby PEt3affordsPt'C10Pt’(78 %), and a Sonogashira reaction ofPt'C2HandPt'ClaffordsPt'C2Pt’(68 %). The analogous reaction withPtC2SiandPtClis unsuccessful, presumably for steric reasons. The crystal structures ofPtC10Pt,PtC14Pt,Pt'C10Pt′, andPt'C2Pt’exhibit a number of interesting trends and features. Certain sp chain extension reactions that lead to or employ the precursorsPtC10Si,PtC12Si,PtC14Si, andPtC18Sisometimes give byproducts derived from C2loss, and possible origins are discussed. Related phenomena have been reported by others in the course of synthesizing extended conjugated polyynes.
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Lewis Acidity of the SbCl 3 / o ‐chloranil System
Abstract While SbCl3is typically inert toward oxidation byortho‐quinones, we useo‐chloranil to show that the outcome of such reactions may be altered by the presence of a donor such as triphenylphosphine oxide, which readily traps the SbCl3(catCl) synthon (catCl = tetrachlorocatecholate) in the form of the corresponding adduct Ph3PO→SbCl3(catCl). The same reaction in the presence of a chloride salt affords the corresponding antimonate anion [Cl4Sb(catCl)]−. Computational studies indicate that the putative SbCl3(catCl) synthon has a higher chloride ion affinity than SbCl5, suggesting significant Lewis acidity. This property is further demonstrated by the use of the SbCl3/o‐chloranil system for both THF polymerization and a Friedel–Crafts‐type alkylation of benzene using 1‐fluorooctane. Finally, the reaction ofE‐stilbene witho‐chloranil in the presence of SbCl3affords the corresponding benzodioxene, suggesting that SbCl3may also operate as a redox‐active catalyst.
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- Award ID(s):
- 2316689
- PAR ID:
- 10592010
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 64
- Issue:
- 29
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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