Allylations of [(diethoxyphosphinyl)difluoromethyl]zinc bromide as a convenient route to 1,1-difluoro-3-alkenephosphonates

Preparation of gem-difluorinated retrohydroxamic-fosmidomycin

“…Both fluorinated fosmidomycin analogues 4 and 12 were not active on the biological tests for determination of herbicide activity. were monitored by 31 Diethyl (3-(benzyloxyamino)-1,1-difluoropropyl)phosphonate 10. In a 500 mL two-necked flask were introduced diethyl 1,1-difluoro-3-oxopropylphosphonate 9 (3.0 g, 13 mmol), Obenzyl-hydroxylamine (1.6 g, 13 mmol) and methanol (10 mL).…”

“…A purification by column chromatography on silica gel with heptane/EtOAc/EtOH as eluent (100:0:0 to 60:36:4) gave 10 as a yellow liquid (3.0 g, 68%). 31 (3-(N-(benzyloxy)acetamido)-1,1-difluoropropyl)phosphonate 11. In a 100 mL twonecked flask were introduced diethyl (3-(benzyloxyamino)-1,1-difluoropropyl)phosphonate 10 (1.2 g, 3.6 mmol), triethylamine (0.58 mL, 4.2 mmol) and CH 2 Cl 2 (30 mL).…”

“…Purification by column chromatography on silica gel with as eluent a mixture of heptane/EtOAc/EtOH (100:0:0 to 50:45:5) gave 11 ( 1.2 g, 86%). 31 1-difluoro-3-(N-hydroxyacetamido)propyl)phosphonate 12. In a Schlenck tube under nitrogen were introduced palladium dihydroxide on charcoal (150 mg, 10%) and 11 (1.5 g, 4.0 mmol) in degassed ethanol (100 mL).…”

Synthesis of 5,5-difluoro-5-phosphono-pent-2-en-1-yl nucleosides as potential antiviral agents

“…Based on our previous work on the preparation of unsaturated acyclic nucleoside phosphonate using olen cross-metathesis as key step, [10][11][12] we decided to utilize this reaction between the unsaturated gem-diuorophosphonate 3 and N 1 -crotylated N 3protected thymine. 10 The key intermediate 3 was synthesized from (diethoxyphosphinyl)diuoromethyl zinc bromide (2), allylic iodine, under CuBr catalysis, following the procedure introduced by Burton et al 13,14 Compound 3 was then engaged in the reaction of cross metathesis in presence of N 3 -benzoyl-N 1crotylthymine 4 with Grubbs-Nolan catalyst 15 in dichloromethane. If cross-metathesis reactions were reported with uorinated substrates, 16 despite all our attempts and contrary to our results with non-uorinated phosphonate derivatives, we never obtained the desired product (Scheme 1); this could be due to the strong electron-withdrawing effect of the 2-gem-diuoro group and to the low reactivity of both cross partners with the metal alkylidene complex.…”

An insight into copper catalyzed allylation of alkyl zinc halides. Comparison of reactivity profiles for catalytic and stoichiometric alkylzinc–copper reagents

“…However, the regiochemistry in the uncatalyzed [24,28] and copper catalyzed allylation of alkylzinc halides and dialkylzincs was reported to be c-selective [25,[29][30][31][32][33]. Allylation of dialkyl zinc cuprates and alkyl cyanozinc cuprates was also reported to take place with high c-selectivity [29,[34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51].…”