304915-07-9

Upstream product

• 2146-67-0 (dichloromethyl)lithium 
• 304915-06-8 (4S,5S)-4,5-dicyclohexyl-2-[[(1,1-dimethylethyl)dimethylsilyl]oxy]methyl-1,3,2-dioxaborolane 
• 18162-48-6 tert-butyldimethylsilyl chloride 
• 304915-05-7 (4S,5S)-4,5-dicyclohexyl-2-hydroxymethyl-1,3,2-dioxaborolane 
• 304915-04-6 (4S,5S)-4,5-dicyclohexyl-2-(benzyloxy)methyl-1,3,2-dioxaborolane 

Downstream Products

• 1415692-97-5 (1S,2S,3R,5S)-pinanediol (1S,2S)-[2-benzyloxy-3-(tert-butyldimethylsilyloxy)-1-(2-oxyethyl)-propyl]boronate 
• 1415692-94-2 [(1S,2S,3R,5S)-pinanediol (S)-[1-benzyloxy-2-(tert-butyldimethylsilyloxy)ethyl]boronate] 
• 1415692-95-3 (1S,2S,3R,5S)-pinanediol (1S,2R)-[2-benzyloxy-1-bromo-3-(t-butyldimethylsilyloxy)propyl]boronate 
• 1415692-96-4 (1S,2S,3R,5S)-pinanediol (1S,2S)-[1-allyl-2-benzyloxy-3-(t-butyldimethylsilyloxy)propyl]boronate 
• 1415692-93-1 (4S,5S)-2-[(1S)-2-[(tert-butyldimethylsilyl)oxy]-1-(benzyloxy)ethyl]-4,5-dicyclohexyl-1,3,2-dioxaborolane 
• 304915-11-5 [2(1R,2R,3S),4S,5S]-4,5-dicyclohexyl-2-[3-azido-1-bromo-2-cyanomethyl-4-[[(1,1-dimethylethyl)dimethylsilyl]oxy]butyl]-1,3,2-dioxaborolane 
• 304915-10-4 (1R,2S,4S,5S)-4,5-dicyclohexyl-2-[2-azido-1-cyanomethyl-3-[[(1,1-dimethylethyl)dimethylsilyl]oxy]propyl]-1,3,2-dioxaborolane 
• 304915-09-1 (1R,2R,4S,5S)-4,5-dicyclohexyl-2-[2-azido-1-bromo-3-[[(1,1-dimethylethyl)dimethylsilyl]oxy]propyl]-1,3,2-dioxaborolane 
• 304915-08-0 [2(1S),4S,5S]-4,5-dicyclohexyl-2-[1-azido-2-[[(1,1-dimethylethyl)dimethylsilyl]oxy]ethyl]-1,3,2-dioxaborolane 

Relevant academic research and scientific papers

Synthesis and properties of 1-(3′-dihydroxyboryl-2′,3′- dideoxyribosyl)pyrimidines

Nucleoside analogues having a boronic acid in place of the 3-hydroxyl group of deoxyribose have been synthesized. The synthesis of 3′-dihydroxyboryl- 2′,3′-dideoxyribose was based on asymmetric homologation of boronic esters with (dihalomethyl)lithium, beginning from a (silyloxymethyl)boronic ester. A change of chiral director is required before introduction of the second stereocenter, and the direct displacement of (S,S)-1,2-dicyclohexyl-1,2- ethanediol by (1S,2S,3R,5S)-pinanediol was used for this purpose. Coupling of the pinanediol ester of the 1-acetoxy-3-dioxyboryl-5-tert-butylsilyloxy deoxyribose analogue with silylated pyrimidine bases was accomplished with trimethylsilyl bromide. The boronic acid nucleoside analogues were not cytotoxic toward Hep G2 (human hepatocarcinoma) cells. Decomposition occurred over a period of several hours at 37 °C, pH 7.4, with liberation of free pyrimidine base.

Asymmetric homologation of boronic esters bearing azido and silyloxy substituents

In the asymmetric homologation of boronic esters with a (dihalomethyl)lithium, substituents that can bind metal cations tend to interfere. Accordingly, we undertook the introduction of weakly basic oxygen and nitrogen substituents into boronic esters in order to maximize the efficiency of multistep syntheses utilizing this chemistry. Silyloxy boronic esters cannot be made efficiently by direct substitution, but a (hydroxymethyl)boronic ester has been silylated in the usual manner. Conversion of (α-halo boronic esters to α-azido boronic esters has been carried out with sodium azide and a tetrabutylammonium salt as phase-transfer catalyst in a two-phase system with water and either nitromethane or ethyl acetate. These are safer solvents than the previously used dichloromethane, which can form an explosive byproduct with azide ion. Boronic esters containing silyloxy or alkoxy and azido substituents have been shown to react efficiently with (dihalomethyl)-lithiums, resulting in efficient asymmetric insertion of the halomethyl group into the carbon-boron bond.