The frustrated Lewis pairs (FLPs) derived from tBu 3 P and E(C 6 F 5 ) 3 (E = B, Al) react with pO 2 C 6 Cl 4 and Ph 3 SnH to give [tBu 3 POC 6 Cl 4 OE(C 6 F 5 ) 3 ] (E = B 1, Al 2), [tBu 3 PSnPh 3 ][HB(C 6 F 5 ) 3 ] 3, and [tBu 3 PSnPh 3 ][(m-H)(Al(C 6 F 5 ) 3 ) 2 ] 4. These products form via the accepted two-electron process involving a transient ''encounter complex.'' In contrast, the corresponding reactions of Mes 3 P and E(C 6 F 5 ) 3 (E = B, Al) with pO 2 C 6 Cl 4 give [(Mes 3 POC 6 Cl 4 OE(C 6 F 5 ) 3 ] (E = B 8, Al 9); however, the identification of the intermediates [Mes 3 P$] 2 [(C 6 F 5 ) 3 EOC 6 Cl 4 OE(C 6 F 5 ) 3 ] (E = B 5, Al 6) supports a mechanism that proceeds via a single-electron transfer process. This is further supported by the reactions of Mes 3 P and E(C 6 F 5 ) 3 (E = B, Al) with Ph 3 SnH, which yielded [Mes 3 PH] [HB(C 6 F 5 ) 3 ] 10 and [Mes 3 PH][(m-H)(Al(C 6 F 5 ) 3 ) 2 ] 11, respectively, with the concurrent formation of Ph 3 SnSnPh 3 .
Single electron transfer (SET) reactions are effected by the combination of a Lewis acid (e.g., E(CF) E = B or Al) with a small molecule substrate and decamethylferrocene (Cp*Fe). Initially, the corresponding reactions of (PhS) and (PhTe) were shown to give the species [Cp*Fe][PhSB(CF)] 1 and [Cp*Fe][(μ-PhS)(Al(CF))] 2 and [Cp*Fe][(μ-PhTe)(Al(CF))] 3, respectively. Analogous reactions with di-tert-butyl peroxide yielded [Cp*Fe][(μ-HO)(B(CF))] 4 with isobutene while with benzoyl peroxide afforded [Cp*Fe][PhC(O)OE(CF)] (E = B 5, Al 6). Evidence for a radical pathway was provided by the reaction of PhSnH and p-quinone afforded [Cp*Fe][HB(CF)] 7 and [Cp*Fe][(μ-OCH)(E(CF))] (E = B 8, Al 9). In addition, the reaction of TEMPO with Lewis acid and Cp*Fe afforded [Cp*Fe][(CHMeNOE(CF)] (E = B 10, Al 11). Finally, reactions with O, Se, Te and S gave [Cp*Fe][((CF)Al(μ-O)Al(CF))] 12, [Cp*Fe][((CF)Al(μ-Se)Al(CF))] 13, [Cp*Fe][(μ-Te)(Al(CF))] 14 and [Cp*Fe][(μ-S)B(CF))] 15, respectively. The mechanisms of these SET reactions are discussed, and the ramifications are considered.
Reaction of (Idipp)AlH3 with [Ph3C][B(C6F5)4] in toluene affords the dimeric aluminum dication [((Idipp)AlH(μ-H))2][B(C6F5)4]22. In contrast, the reaction of (IBn)AlH3 with [Ph3C][B(C6F5)4] in bromobenzene gives a redistribution product, the salt of a monomeric dication [(IBn)2AlH][B(C6F5)4]24.
The reactions of the cyclic alkyl amino carbene (CAAC) 1 with phosphaalkynes generate the kinetically unstable CAAC‐derived phosphirenes 4 and 5, which undergo rearrangement/dimerization reactions to give the vinyl‐substituted diphosphenes 2, 3, and 6. The P=P double bond scission of 2 or 3 is unprecedentedly effected by S8, [AuCl(tht)], or MeOTf at room temperature, which affords a dithiophosphorane 7, a phosphepine Au complex 8, or phosphepinium cations 9 and 10, respectively. The cationic species feature little homoaromaticity while representing the first examples of the phosphorus‐containing analogue of the tropylium ion.
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