Formation and Structure of Coordinatively Unsaturated CpIr-Amino Acid Complexes. Kinetic and Thermodynamic Control in Highly Diastereoselective Complexation Reactions

Open-Shell Organometallics as a Bridge between Werner-Type and Low-Valent Organometallic Complexes. The Effect of the Spin State on the Stability, Reactivity, and Structure

“…A few isolable 16-electron complexes of this type, CLV , have been reported for iridium, e.g. Cp*Ir(η 2 - N , O -amino acid) complexes. , These are stabilized by π-donation from the N and O donors, adopt a planar structure, and are diamagnetic. The addition of phosphines, unhindered amines, or CO immediately generates saturated adducts.…”

Studies of the Synthesis and Thermochemistry of Coordinatively Unsaturated Chelate Complexes (η5-C5Me5)IrL2 (L2 = TsNCH2CH2NTs, TsNCH2CO2, CO2CO2)

“…In 1994, Grotjahn et al reported a series of amino acid complexes featuring Cp*Ir bound to an N -acyl or N -tosyl amino acid ligand, deprotonated at N and carboxylate O . These complexes, represented by N -tosylamidoglycine derivative 2 , were noteworthy for their high stability, coordinative unsaturation, and rapid, stereoselective ligand additions when chiral amino acids were involved. − Spectroscopic and X-ray crystallographic evidence pointed to significant π-donation from the acylated or tosylated nitrogen in 2 , which was reduced upon addition of a ligand L and formation of 5 (Scheme ). , Even though some π-donation from the carboxylato oxygen was assumed, no direct evidence of this was available. Because sulfonamido ligands are increasingly important in organometallic chemistry, it seemed important to clarify structure and bonding in complexes of type 2 .…”

A Chiral N-Sulfonylphosphoramide: Synthesis and X-ray Crystal Structure of a 1,3,2-Oxazaphospholidin-5-one, a Trivalent Electron-Withdrawing Amino Acid-Derived Phosphorus Compound, and Synthesis of Its W(CO)5 Adduct

“…A single crystallization gives one diastereomer in overall 50% yield, and so constitutes one of the simplest syntheses of an enantiomerically pure trivalent phosphorus compound. This work extends the number of sulfonamide-substituted heterocycles that exhibit interesting and high stereoselectivity, 6a,c so exploration of the steric space of this substituent appears to be in order. Future research will be directed toward understanding the factors that contribute to diastereoselectivity at phosphorus, stereospecific transformations of this new phosphorus heterocycle, and use in catalytic reactions.…”