Enzymes in organic chemistry, part 2: Lipase-catalysed hydrolysis of 1-acyloxy-2-arylethylphosphonates and synthesis of phosphonic acid analogues of L-phenylalanine and L-tyrosine

An efficient and general route to the synthesis of diethyl α,α-bromofluorophosphonates

“…The starting materials, a-hydroxyphosphonates 1, were obtained in excellent yields from corresponding aldehydes and diethyl phosphate with sodium ethoxide as catalyst [7]. The following step was nucleophilic bromination.…”

Synthesis and Reactivity of Azidoalkylphosphonates, -Phosphinates and -Phosphine Oxides

“…Similarly, diisopropyl (R)-azido(aryl)methylphosphonates 11g,h [26] were obtained in good yields. Chiral non-racemic allylic azido(aryl)methylphosphonates 11i-k [29] were prepared in 88-98% yield by the Mitsunobu azidation starting from hydroxyphosphonates 10i-k [30].…”

“…In that way a range of (R)-1-azidoalkyl-and (R)-azido(aryl)methylphosphonates 11 were obtained in a stereospecific manner from (S)-hydroxy analogs 10 using the Ph 3 P/DEAD/HN 3 system in good to excellent yield after flash chromatography. Depending on the structure of the starting hydroxyphosphonates 10 different ratios of reagents and reaction conditions had been applied [18,[26][27][28][29] (Scheme 5).…”

Successful Application of the Lipase as a Catalyst in the Combinative Approach, Using an Efficient and Selective Iterative Procedure for the Chemo-Enzymatic Alpha-Amino Group Protection in the Natural Amino Acids, Representing the Ornithyl Model System as a Starting Research Pattern: Homogeneous and Heterogeneous Synthesis

“…The most successful solvent combination depends on the procedure for protection (synthesis), which in turn is determined and restricted by the nucleophilic specificity and respectively by the "pool" species and identity, nature, specificity and character of the components and therefore depending on the component excess. The most general, frequently and commonly utilizing solvents combination, which were used is a mixture of polar solvents with the water solution of sodium carbonate (pH 9-9.3): DMSO/Na 2 CO 3 , acetone/Na 2 CO 3 , CH 3 CN/Na 2 CO 3 , DMF/Na 2 CO 3 , MeOH/Na 2 CO 3 , ethylene glycol/ Na 2 CO 3 , propylene glycol/Na 2 CO 3 , isopropylene glycol/Na 2 CO 3 -one phase system (in the case, when the enzyme is dissolved) [28] ☼ , as well as a combination of non-polar solvents with water solution of sodium carbonate (pH 9-9.3): CHCl 3 /Na 2 CO 3 or CH 2 Cl 2 /Na 2 CO 3 -two phase system, or one phase: CHCl 3 or CH 2 Cl 2 and triethylamine as a base (in the presence of immobilized lipase) [28]. As a result of the using of different nucleophilic and electrophilic components -the approach is chosen, which therefore depends on the different nucleophilic and electrophilic specificity, hence the conclusion is that an excess (different molar ratios) from the amino component -nucleophile ("nucleophile pool") or acyl component -electrophile ("electrophile pool") is allowed to be used and had to be added to the reaction mixture (Figure 2).…”