Reduction of organic compounds with diborane

Lane, Clinton F.

doi:10.1021/cr60304a005

Cited by 150 publications

(55 citation statements)

References 62 publications

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“…Furthermore, we verified that reactions of the BH 3 ·THF adduct, formed eventually during the initiation process, with the incoming monomer or with the growing polymer chain are not observed, as reported previously. [50] In addition, the formate end group of methyl formate remains unaffected by the borane adduct. However, whatever the exact circumstances of BH 3 ·THF elimination, the whole process leads to a final polymer that always exhibits formate and hydroxyl chain ends, HO-PTMC-OC(O)H, 4.…”

Section: Mechanistic Insightsmentioning

confidence: 99%

Unprecedented Polymerization of Trimethylene Carbonate Initiated by a Samarium Borohydride Complex: Mechanistic Insights and Copolymerization with ε‐Caprolactone

Palard

Schappacher

Belloncle

et al. 2007

Chemistry A European J

106

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Poly(trimethylene carbonate) (PTMC) was synthesized through ring-opening polymerization by using a rare-earth borohydride initiator, [Sm(BH(4))(3)(thf)(3)]. This initiator shows a high activity to give high-molar-mass PTMCs with molar-mass distributions ranging from 1.2 to 1.4, and with a regular structure void of ether linkages. The polymers were characterized by (1)H and (13)C NMR spectroscopy, (1)H-(1)H COSY, (1)H-(13)C HMQC NMR spectroscopy, size-exclusion chromatography (SEC), viscosimetry, and MALDI-TOF MS analyses. A coordination-insertion mechanism was established based on detailed NMR characterizations, especially of the polymer chain end-functions. The monomer initially coordinates the samarium to give [Sm(BH(4))(3)(tmc)(3)], 1. The monomer then opens up through cleavage of the cyclic ester oxygen--acyl bond and inserts into the Sm--HBH(3) bond resulting in an alkoxide complex, [Sm{O(CH(2))(3)OC(O)HBH(3)}(3)], 2, or [Sm{O(CH(2))(3)OC(O)H}(3)], 2', which then propagates the polymerization of TMC to give the active polymer [Sm({O(CH(2))(3)OC(O)}(n)O(CH(2))(3)OC(O)HBH(3))(3)], 3 or [Sm(O(CH(2))(3)OC(O){O(CH(2))(3)OC(O)}(n)O(CH(2))(3)OC(O)H)(3)], 3'. Finally, acidic hydrolysis of 3 or 3' gives HO(CH(2))(3)OC(O)[O(CH(2))(3)OC(O)](n)O(CH(2))(3)OC(O)H, 4. This novel alpha-hydroxy,omega-formatetelechelic PTMC represents the first example of a formate-terminated polycarbonate. TMC and epsilon-caprolactone (CL) were copolymerized to afford both random PTMC-co-PCL and block PTMC-b-PCL copolymers that were characterized by (1)H NMR spectroscopy, SEC, and differential scanning calorimetry (DSC). The structure of the block copolymers depends on the order of addition of monomers: if CL is introduced first, dihydroxytelechelic HO-PTMC-b-PCL-OH polymers are formed, whereas introduction of TMC first or simultaneous addition of comonomers leads to hydroxyformatetelechelic HC(O)O-PTMC-b-PCL-OH analogues.

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Section: Mechanistic Insightsmentioning

confidence: 99%

Unprecedented Polymerization of Trimethylene Carbonate Initiated by a Samarium Borohydride Complex: Mechanistic Insights and Copolymerization with ε‐Caprolactone

Palard

Schappacher

Belloncle

et al. 2007

Chemistry A European J

106

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“…The addition of a stoichiometric amount of BMS to a solution undec 10-enoic acid in THF results in the instantaneous formation of an insoluble polymer (Lane, 1976). That is probably due to the acid function of reduction reaction that is much more reactive than the carbon-carbon unsaturation.…”

Section: Resultsmentioning

confidence: 99%

Hydroboration of Methyl Esters of Fatty Acids

Mcheik

Hijazi

Diab

et al. 2017

ESJ

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Hydroboration addition reactions of a boron atom, and hydrogen over unsaturated, have been widely studied. They have excellent access routes to organoborans which have proven to be a very useful synthetic intermediate Matteson, 1987;Smith, 1994). The bill might be on one or other of the two carbons of the unsaturation. It is carried out preferentially along the least congested carbon (anti-Markownikov addition). This regioselectivity can be changed against steric effects (Brown & Zweifel, 1960;Brown & Sharp, 1968;Brown et al., 1974). The existence of two active sites in methyl esters of fatty acids, FAME: the carbon-carbon unsaturation and the ester, make their hydroboration reactions more difficult to achieve. However, it has been demonstrated that reducing the ester groups is much slower than that of olefins (Brown & Keblys, 1964). By using suitable operating conditions, it is possible to limit this secondary reaction and to obtain a selective reaction of carboncarbon double bond (Fore & Bickford, 1959). Others have protecting ester function by a silyl group in order to have a single reactive site (Kabalka & Bierer, 1989).

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“…For this purpose, deuterated diborane was freshly prepared by reaction of boron trifluoride diethyl etherate and sodium borodeuteride. [39][40][41] The suspension was slowly added to the carboxylic acid derivative 9 in dry tetrahydrofuran. The reduction preceded smoothly giving the deuterium labelled alcohol 10 in 76% yield with complete incorporation of deuterium.…”

Section: Chemistrymentioning

confidence: 99%

Gas phase production of [¹¹C]methyl iodide‐d₃. Synthesis and biological evaluation of S‐[N‐methyl‐¹¹C]citalopram and deuterated analogues

Madsen

Elfving

Andersen

et al. 2004

Labelled Comp Radiopharmac

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Reduction of organic compounds with diborane

Cited by 150 publications

References 62 publications

Unprecedented Polymerization of Trimethylene Carbonate Initiated by a Samarium Borohydride Complex: Mechanistic Insights and Copolymerization with ε‐Caprolactone

Unprecedented Polymerization of Trimethylene Carbonate Initiated by a Samarium Borohydride Complex: Mechanistic Insights and Copolymerization with ε‐Caprolactone

Hydroboration of Methyl Esters of Fatty Acids

Gas phase production of [¹¹C]methyl iodide‐d₃. Synthesis and biological evaluation of S‐[N‐methyl‐¹¹C]citalopram and deuterated analogues

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Reduction of organic compounds with diborane

Cited by 150 publications

References 62 publications

Unprecedented Polymerization of Trimethylene Carbonate Initiated by a Samarium Borohydride Complex: Mechanistic Insights and Copolymerization with ε‐Caprolactone

Unprecedented Polymerization of Trimethylene Carbonate Initiated by a Samarium Borohydride Complex: Mechanistic Insights and Copolymerization with ε‐Caprolactone

Hydroboration of Methyl Esters of Fatty Acids

Gas phase production of [11C]methyl iodide‐d3. Synthesis and biological evaluation of S‐[N‐methyl‐11C]citalopram and deuterated analogues

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Gas phase production of [¹¹C]methyl iodide‐d₃. Synthesis and biological evaluation of S‐[N‐methyl‐¹¹C]citalopram and deuterated analogues