96553-70-7Relevant academic research and scientific papers
Selective functional transformation of 1,2-diols via organophosphorus reagents
Pirat, Jean-Luc,Carteron, Michel,Maggio, Annie-Francoise,Bot, Stephanie,Cristau, Henri-Jean
, p. 609 - 612 (2007/10/03)
A new synthesis of 1,3,2λ5-dioxaphospholanes was realized by direct reaction of dibromotriphenylphosphorane with 1,2-diols. Ring opening studies were performed with or without electrophilic activation (Lewis acids or hydrogen bonding) in order to substitute selectively one of the hydroxy function.
Lewis Acid Promoted Decomposition of Substituted 1,3,2λ5-Dioxaphospholanes: Kinetic and Thermodynamic Studies
Murray, William T.,Evans, Slayton A.
, p. 2440 - 2446 (2007/10/02)
The kinetics of Lewis acid mediated decomposition of a series of substituted 1,3,2λ5-dioxaphospholanes, prepared by transphosphoranylation of 1,2-diols with diethoxytriphenylphosphorane (DTPP), is reported.The rate data obtained from 31P NMR spectroscopic measurements, emphasize the influence of (i) variations in the coordination potential (i.e., cationic charge) of the Lewis acids, (ii) methyl group substitution at C-4 and C-5 in the 1,3,2λ5-dioxaphospholanyl substructure, and (iii) changes in solvent polarity.Also, the propensity for 1,2-hydride migratory processes attending conformationally restricted bicyclic 1,3,2λ5-dioxap hospholanes versus epoxide formation from the collapse of simple cyclic 1,3,2λ5-dioxaphospholanes were examined.The results are best explained by invoking a "site-selective" coordination by the catalyst to one of the "ethereal" oxygens within 1,3,2λ5-dioxaphospholanyl moiety initiating P-O bond cleavage and ultimately affording the requisite betaine intermediate(s).Methyl substitution on the 1,3,2λ5-dioxaphospholanyl hydrocarbon backbone decreases the rate of P-O bond cleavage, and the 1,2-hydride migratory process within conformationally rigid bicyclic 1,3,2λ5-dioxaphospholanes requires ca. 2.0 kcal/mol more energy than the decomposition of the monocyclic 1,3,2λ5-dioxaphospholanes via 3-exo-tet cyclization to the respective cyclic ethers.Mechanistic implications of various reactions are discussed.
THE SYNTHETIC UTILITY OF DIOXYPHOSPHORANES IN ORGANIC SYNTHESIS
Robinson, Philip L.,Kelly, Jeffery W.,Evans, Slayton A.
, p. 15 - 24 (2007/10/02)
Diethoxytriphenylphosphorane, DTPP, prepared by reaction of triphenylphosphine and diethyl peroxide, is a "hydrolytically active" dioxyphosphorane which promotes mild and efficient cyclodehydration of diols to cyclic ethers in neutral media.Simple 1,2-, 1,4-, and 1,5-diols afford good yields of the cyclic ethers but 1,3-propanediol and 1,6-hexanediol give mainly 3-ethoxy-1-propanol and 6-ethoxy-1-hexanol, respectively, with DTPP.Tri- and tetra-substituted 1,2-diols afford the relatively stable 1,3,2-dioxaphospholanes in the presence of DTPP and the reaction conditions dictate whether epoxides, ketones, or allylic alcohols are obtained.
Reactions of Diethoxytriphenylphosphorane with Diastereoisomeric 3-Methylcyclohexane-1,2-diols. Control of Regioselectivity by Methyl Substitution during Cyclodehydration and Rearrangement of 1,2-Diols
Robinson, Philip L.,Evans, Slayton A.
, p. 3860 - 3863 (2007/10/02)
The diastereoisomeric 3-methylcyclohexane-trans-1,2-diols undergo cyclodehydration with diethoxytriphenylphosphorane (DTPP) to afford the cis- and trans-3-methylcyclohexene oxides.The ratio of cis and trans epoxides is best explained by assuming preferential phosphoranylation of the C1 hydroxyl group followed by " 3-exo-tet " alkoxide displacement of triphenylphosphine oxide.The diastereoisomers of 3-methylcyclohexane-cis-1,2-diol afford stable ? -dioxyphosphoranes when allowed to react with DTPP.These 1,3,2-dioxaphosphoranes were subjected to flash thermolysis ( 300 deg C ) conditions and afforded the isomeric 2- and 3-methylcyclohexanones via a 1,2-hydride shift.
Diethoxytriphenylphosphorane: A Mild, Regioselective Cyclodehydrating Reagent for Conversion of Diols to Cyclic Ethers. Stereochemistry, Synthetic Utility, and Scope
Robinson, Philip L.,Barry, Carey N.,Kelly, Jeffery W.,Evans, Slayton A.
, p. 5210 - 5219 (2007/10/02)
Diethoxytriphenylphosphorane, Ph3P(OEt)2, prepared by reaction of triphenylphosphine and diethyl peroxide, is a "hydrolytically active" dioxyphosphorane which promotes mild cyclodehydration (40-110 deg C) of diols to cyclic ethers in neutral media.The regioselectivity in the closure of (S)-(+)-propane-1,2-diol and (R)-(-)-pentane-1,4-diol with Ph3P(OEt)2 is high (81-82 percent) while the cyclodehydration of (S)-(+)-phenylethane-1,2-diol gives racemized (+/-)-styrene oxide.Simple 1,2-, 1,4-, and 1,5-diols afford good yields of the cyclic ethers but 1,3-propanediol and 1,6-hexanediol give mainly 3-ethoxy-1-propanol and 6-ethoxy-1-hexanol, respectively with Ph3P(OEt)2.Tri- and tetra-substituted 1,2-diols afford the relatively stable 1,3,2-dioxaphospholanes (or ?-dioxyphosphoranes) in the presence of Ph3P(OEt)2, and, depending on conditions, the 1,3,2-dioxaphospholanes are selectively converted to epoxides, ketones or allylic alcohols.The carbonyl compounds arise from 1,2-hydride and 1,2-methyl migrations; the allylic alcohols are derived from thermolytic eliminations. trans-1,2-Cyclohexanediols afford essentially quantitative yields (>95 percent) of the cyclohexene oxides while cis-1,2-cyclohexanediol gives the stable 1,3,2-dioxaphospholane with Ph3P(OEt)2 which decomposes under thermal conditions to cyclohexanone (90 percent).Ph3P(OEt)2 is extremely useful for conversion of "sensitive" 1,2-diols to acidic and /or thermally labile epoxides as demonstrated by the quantitative conversion of 9,10-dihydro-trans-9,10-phenanthrenediol to 9,10-dihydrophenanthrene oxide and 2α,10-pinanediol to 2α,10-epoxypinane.
