Progress in transition metal-based enantioselective catalysis

Abstract

In Chapter 1, the first enantioselective cross-coupling reactions of racemic secondary benzylic halides are described (eq 1). This method was applied to the syntheses of intermediates employed by other groups in the generation of bioactive compounds, e.g., an androgen receptor agonist (1.1) and two members of the trikentrin family of natural products (1.2 and 1.3). In Chapter 2, the first method for the kinetic resolution of indolines through catalytic Nacylation is described (eq 2). To improve the selectivity factor, a new planar-chiral PPY-erived catalyst (2.1) was prepared, wherein the chiral environment had been modified. The method was applied to the resolution of an intermediate prepared by K. Tsuji in the synthesis of a series of novel antibiotics of core structure 2.2. This work provides a rare example of a nonenzyme-based acylation catalyst for the kinetic resolution of amines. Finally, in Chapter 3, the first examples of catalyzed, enantioselective insertion of carbenoid fragments into C-N sigma bonds are described (eq 3). The system uses commercially-available catalyst components and gives highly enantioselective rearrangements of benzylamine-, allylamine-, and [alpha]-aminocarbonyl-containing substrates. The method represents a new way to access 1,4-benzoxazinones, a subunit present in several pharmaceutical targets and chiral natural products.