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Transition state models are proposed for chiral counterion induced stereoselectivity in cooperative dual catalysis access to the amination of alcohols., Asymmetric catalysis using two chiral catalysts in combination using one-pot reaction conditions is in its initial stages of development and understanding. We employ density functional theory (SMD(toluene)/M06/6-31G**,SDD(Ir)) computations to shed light on the action of chiral phosphoric acid and a chiral Cp*Ir(diamine) in stereoinduction in an asymmetric amination reaction of an alcohol. First, the protonation of the Ir–diamine complex by the phosphoric acid forms an ion-pair of the active catalytic dyad. Both chiral catalysts are involved throughout the catalytic cycle, thus constituting an important example of true cooperative catalysis. A borrowing hydrogen mechanism operates, wherein the phosphate abstracts the hydroxyl proton of the alcohol while the electrophilic Ir(iii) simultaneously extracts the α-hydrogen to form a [Ir]–H species. The ketone thus derived from the alcohol through dehydrogenation condenses with aniline to form an imine. In the diastereocontrolling transition state, the hydride adds to the activated iminium, held in position in the chiral pocket of the catalytic dyad through a network of noncovalent interactions (C–H···π, N–H···O and C–H···O). The enantioselectivity in this DYKAT process is identified as taking place at an earlier stage of the catalytic cycle prior to the diastereo-determining transition state.

Building up on an available synthetic methodology, phosphate monoesters ROPO3H2 have been synthesized in good yields. The synthetic procedure employed features acetic anhydride mediated activation of phosphoric acid in the presence of alcohols, leading to the formation of phosphate monoesters. The products have been isolated as their cyclohexyl amine salts, [CyNH3](2)[(MeO)PO3]center dot 3H(2)O (1) and [CyNH3][(RO)PO3H] (Cy = cyclohexyl; R = Et (2), iPr (3), or tBu (4)). Neutralization of 1-4 by readily available inexpensive ion exchange resin Amberlite produces monoalkylphosphates (RO)P(O).OH)(2) (R = Me (5), Et (6), iPr (7), or tBu (8)). Thermally labile 1-4 and 7 have been structurally characterized by single crystal X-ray diffraction studies. Due to their intrinsic thermal instability due to beta-H elimination, these compounds can be used as ligands for the preparation of single-source precursors for ceramic phosphates by reacting them with suitable metals ions. It is also possible to isolate co-crystals of the anionic and neutral forms of these phosphates as it has been demonstrated in the isolation and structural characterization of [(iPrO)PO3H2]center dot{[CyNH3][(iPrO)PO3H]} (9). To demonstrate the utility of these monoalkylphosphates in the low-temperature synthesis of metal phosphate bioceramics, isopropyl phosphate 7 has been employed to prepare calcium phosphate [{Ca((iPrO)PO3)(OH2)}center dot H2O] n (10), which undergoes neat thermal decomposition in two stages to lose water and propene to yield beta-Ca2P2O7 at low temperatures (280 degrees C).