Iridium(I) Complexes of Upper Rim Functionalized PTA Derivatives. Synthesis, Characterization, and Use in Catalytic Hydrogenations (PTA = 1,3,5-Triaaza-7-phosphaadamantane)

Reaction of (1,3,5-triaza-7-phosphaadamantane-6-yl)lithium (1; PTA-Li), synthesized in high yield and purity, with p-(dimethylamino)benzaldehyde gave the novel water-soluble β-phosphino alcohol (4′-(dimethylamino)phenyl)(1,3,5-triaza-7-phosphatricyclo[3.3.1.1]dec-6-yl)methanol (2; PZA-NMe2). The oxide OPZA-NMe2 (3) and sulfide SPZA-NMe2 (4) were also obtained. Ir(I) complexes of (SR,RS)-PZA-NMe2 and the analogue phenyl(1,3,5-triaza-7-phosphatricyclo[3.3.1.1]dec-6-yl)methanol (PZA) were obtained and used as precatalysts for the hydrogenation of α,β-unsaturated aldehydes and ketones and acetophenone using different mild reduction protocols. The X-ray crystal structure of the SR,RS diastereoisomer of PZA-NMe2 was also obtained and is described herein.