Ferrocenyl-aminophosphine

Early studies on palladium-catalyzed asymmetric hydrosilylation of cyclic conjugated dienes employing menthyl-, neomenthyl-diphenylphosphine, and ferrocenyl-aminophosphine ligands gave low enantiomeric excesses of the corresponding allylsilane [13]. 

Oxazaphospholidine boranes 82 react regio- and stereoselectively with alkyl lithiums or aryl lithiums in THE at —78°C, with formation of acyclic phosphinite boranes 83. Various substituents R =n-alkyl, c-alkyl, aryl, or ferrocenyl were introduced into aminophosphine boranes 82 in high yield (93-97%) and with high diastereoselectivity dr >98 2). The reaction proceeded with retention of configuration at phosphorus. RecrystaUization of aminophosphine boranes 83 in propanol gave the diastereoisomerically pure products [53]. Acid methanolysis of aminophosphine boranes 83 led to the formation of phosphinite boranes 84 with inversion of configuration on the E-center to yield the compotmds 84 in high... 

Other bulky phosphines have been employed in cross-coupling reactions, involving numerous substrates with various efficiency, such as BINAP [20], ferrocenyl phosphines (with a maximum TON of 250000) [21], tetradentate phosphines (0.01 mol% catalyst for the conversion of aryl chlorides) [22], aminophosphines... 

The reaction is also troublesome when the precursor contains a ferrocenyl group (entries 41 and 42). Here the reaction is sluggish and low yielding, with around 35% of starting material recovered. In contrast, the methanolysis of a diastereomeric mixture of the Z)zj (aminophosphine) boranes derived from l,l -dilithioferrocene affords 20 in 90% yield but with only 20% of ee (Scheme 4.10). ... 

Applications of ferrocenes are numerous,in particular with the use of ferrocenyl phosphines, including chiral ones (see for insance the aminophosphine below), as ligands for catalysis. l,l -bis(diphenylphosphino)ferrocene (dppf, below) is the best known ferrocenyl-based ligand in the catalysis of most classic reactions, and its chemistry and uses are prolific. The redox property of ferrocene has been used to attach it to macrocycles (below), cryptands, calixarenes and other endo-receptors for sensing, a chemistry beautifully developed by Paul Beer at Oxford,... 

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