1. Introduction and Scope 3297 2. The Use of Achiral Salen Ligands in Asymmetric Catalysis 3305 3. Use of Achiral Biphenol-Based Ligands in Asymmetric Catalysis 3308 3.1. Asymmetric Carbonyl−Ene Reaction 3308 3.2. Asymmetric Addition of Methyl Groups to Aldehydes 3309 3.3. Asymmetric Baeyer−Villiger Oxidation 3309 4. Atropisomeric Biphenyl-Based Phosphines and Related Ligands in Asymmetric Catalysis 3310 4.1. Asymmetric Hydrogenation Reactions Using BIPHEP-Derived Ligands 3311 4.2. Asymmetric Diels−Alder and Carbonyl−Ene Reactions with BIPHEP-Derived Ligands 3313 4.3. Interconversion of Diastereomeric Catalysts and Catalyst Precursors Containing BIPHEP Derivatives 3315 4.4. Mechanistic Aspects of Atropisomerization of BIPHEP 3317 4.5. A Potentially Useful New Class of Achiral Diphosphine Ligands (NUPHOS) 3319 4.6. Complexes of a Meso Cyclohexane-Based Diphosphine 3320 4.7. Spontaneous Resolution of an Asymmetric Catalyst Bearing a Bis(phosphole) Ligand 3320 4.8. A Metallocene Catalyst with a Biphenyl Backbone 3322 4.9. Use of Bis(diphenylphosphino)ferrocene and Related Ligands in Asymmetric Catalysis 3323 4.10. Dynamic Resolution of Bis(phospholyl)−Zr Complexes 3325 5. Examination of the Barrier to Atropisomerization in Biphenyl-Based Diamines 3326

Catalytic and enantioselective synthesis of amino acids is a subject of intense interest in the field of asymmetric catalysis. Traditionally, researchers have concentrated their efforts largely on the design and discovery of enantiopure catalysts for the Strecker reaction, alkylation of tert-butyl gylcinate-benzophenone, electrophilic amination of carbonyl compounds, and hydrogenation of N-acyl-aminoacrylic acid; however, the scope of these reactions is limited. In this paper, we report on a different approach to amino acids based on an expeditious route to enantiopure allylic amines. A highly enantioselective and catalytic vinylation of aldehydes leads to allylic alcohols that are then transformed to the allylic amines via Overman's [3,3]-sigmatropic rearrangement of imidates. Oxidative cleavage of the allylic amines furnishes the amino acids in good yields and excellent ee's. The scope and utility of this method are demonstrated by the synthesis of challenging allylic amines and their subsequent transformation to valuable nonproteinogenic amino acids, including both D and L configured (1-adamantyl)glycine.

In this report, we outline a highly enantio- and diastereoselective one-pot method for the efficient synthesis of synthetically useful acyclic epoxy alcohols and allylic epoxy alcohols. Our method takes advantage of a highly enantioselective C-C bond-forming reaction to set the initial chirality. The resulting allylic zinc alkoxide intermediate is then epoxidized in situ using either dioxygen or TBHP in the presence of a titanium tetraalkoxide. Epoxy alcohols with up to three contiguous stereocenters are formed in one pot with excellent enantio- and diastereoselectivity. In cases where the zinc alkoxide intermediates contain two different allylic olefins, the more electron-rich double bond is chemoselectively epoxidized to afford an allylic epoxy alcohol. This method represents a highly efficient, stereoselective, and chemoselective approach to the synthesis of a wide range of useful epoxy alcohol and allylic epoxy alcohol products that were previously difficult to access.