Planar chiral phosphines displaying a new ferrocenophane scaffold have been prepared via a stereoselective approach. The P-cyclohexyl substituted phosphine affords high levels of asymmetric induction in the organocatalytic [3 + 2] annulation reaction between allenes and electron-poor olefins.

This Review deals with the asymmetric hydrogenation and asymmetric transfer hydrogenation of imines and some nitrogen‐containing heteroaromatic compounds to afford amines. Hydrogenation and transfer hydrogenation are covered in separate sections. Particular attention is devoted to the substrates, since this reaction is highly substrate dependent. In this way the general structural trends in imine hydrogenation are presented, highlighting the more challenging substrates. Since hydrogenation of acyclic and cyclic (including heteroaromatic) imines have some different features they are also presented separately. The catalytic systems are classified according to the metal, and focus on the most successful catalytic systems and metal–ligand combinations. The catalytic cycles for these hydrogenation processes are also proposed.

Copper-catalyzed borylation of a variety of organic halides with bis(pinacolato)diboron allows the preparation of diverse potassium organotrifluoroborates. The reactions are mild and general, providing access to a variety of interesting, boron-containing building blocks, including those containing piperidine, pyrrole, azetidine, tetrahydropyran and oxetane substructures. Representative Minisci reactions are reported for select examples.

The introduction of an alkoxyethyl moiety onto aromatic substructures has remained a long-standing challenge for synthetic organic chemists. The main reasons are the inherent instability of alkoxyethylmetallic species and the lack of general procedures to access them. A new method utilizing a cross-coupling strategy based on the exceptional properties of organotrifluoroborates has been developed, and the method allows an easy and efficient installation of this unit on a broad range of aryl and heteroaryl bromides.

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The use of binaphthophosphepine 1a as a catalyst for the [3+2] cyclisation between allenoates or 2-butynoates and imines was investigated. The effects of the imine protecting group on both the catalytic activity and enantioselectivity were determined by comparing the behaviour of N-tosyland N-DPP-imines. The N-DPP-imines displayed lower reac-

Planar chiral 2-phospha[3]ferrocenophanes have been prepared via a stereoselective three-step synthesis. The key step is the lithiation of the 1,1'-di-A C H T U N G T R E N N U N G substituted ferrocene 11 bearing (S)-2-(methoxymethyl)pyrrolidines as the chiral ortho-directing groups. The diastereoselectivity of these reactions has been mastered by an appropriate choice of the metallating agent, so as to afford a suitable access to C 2 -symmetrical, tetrasubstituted ferrocenes. These compounds have been converted into the enantiomerically pure 2-phospha[3]-ferrocenophanes 16, via the corresponding acetates and their reactions with primary phosphines. Phosphines 16 have been used as nucleophilic catalysts in model cyclization reactions. Unlike 2-phospha[3]-ferrocenophanes with stereogenic acarbons, the planar chiral derivatives 16 proved to be suitable catalysts for these processes. Thus, for instance, phosphine 16c successfully promotes the enantioselective [3 + 2] annulations of allenes and enones into functionalized cyclopentenes (ees up to 96%). Among others, spirocyclic derivatives have been obtained in good yields and ees in the range 77-85%. The robustness of this catalyst has been demonstrated by recycling experiments.