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D-(+)-Camphor forms the enamine 2 with piperidine. Compound 2 adds HB(C(6)F(5))(2) at the enamine carbon atom C3 to form a Lewis acid/Lewis base adduct (exo-/endo-isomers of 3). Exposure of 3 to dihydrogen (2.5 bar, room temperature) leads to heterolytic splitting of H(2) to form the H(+)/H(-) addition products (4, two diastereoisomers) of the "invisible" frustrated Lewis pairs (5, two diastereoisomers) that were apparently generated in situ by enamine hydroboration under equilibrium conditions.

Intramolecular vicinal and geminal frustrated Lewis pairs (FLPs) featuring bulky substituents at phosphorus or nitrogen and strongly electron-withdrawing bulky pentafluorophenyl substituents at boron undergo a variety of addition and/or activation reactions with small molecules. A number of examples of such reactions are presented and discussed, among them the FLP activation of dihydrogen to give zwitterionic phosphonium (or ammonium)/hydridoborate zwitterions. Intramolecular FLPs also add to organic carbonyl compounds (including carbon dioxide), to alkenes and alkynes (including conjugated dienes, diynes or enynes), to heterocumulenes, to azides, and to nitric oxide.

Frustrated Lewis pairs, highly active in heterolytic dihydrogen splitting, were used as active and very selective hydrogenation catalysts for organometallic substrates. Conjugated dienamines fixed at the ferrocene framework and at the zirconocene nucleus were selectively 1,4-hydrogenated under catalytic conditions at ambient temperature.

Intramolecular vicinal and geminal frustrated Lewis pairs (FLPs) featuring bulky substituents at phosphorus or nitrogen and strongly electron-withdrawing bulky pentafluorophenyl substituents at boron undergo a variety of addition and/or activation reactions with small molecules. A number of examples of such reactions are presented and discussed, among them the FLP activation of dihydrogen to give zwitterionic phosphonium (or ammonium)/hydridoborate zwitterions. Intramolecular FLPs also add to organic carbonyl compounds (including carbon dioxide), to alkenes and alkynes (including conjugated dienes, diynes or enynes), to heterocumulenes, to azides, and to nitric oxide.

Intramolecular vicinal and geminal frustrated Lewis pairs (FLPs) featuring bulky substituents at phosphorus or nitrogen and strongly electron-withdrawing bulky pentafluorophenyl substituents at boron undergo a variety of addition and/or activation reactions with small molecules. A number of examples of such reactions are presented and discussed, among them the FLP activation of dihydrogen to give zwitterionic phosphonium (or ammonium)/hydridoborate zwitterions. Intramolecular FLPs also add to organic carbonyl compounds (including carbon dioxide), to alkenes and alkynes (including conjugated dienes, diynes or enynes), to heterocumulenes, to azides, and to nitric oxide.

A series of enamines undergoes anti-Markovnikov hydroboration with Piers' borane HB(C6F5)2 to yield C2-bridged frustrated N/B Lewis pairs, featuring weak N⋯B interaction. Some examples show typical frustrated Lewis pair reactions with dihydrogen or with 1-alkynes. One such N/B FLP serves as an active catalyst for the hydrogenation of enamines. Many of the new compounds were characterized by X-ray diffraction.