765-04-8Relevant articles and documents
Borane evolution and its application to organic synthesis using the phase-vanishing method
Soga, Nene,Yoshiki, Tomo,Sato, Aoi,Kawamoto, Takuji,Ryu, Ilhyong,Matsubara, Hiroshi
supporting information, (2021/03/26)
Although borane is a useful reagent, it is difficult to handle. In this study, borane was generated in situ from NaBH4 or nBu4NBH4 with several oxidants using a phase-vanishing (PV) method. The borane generated was directly reacted with alkenes, affording the desired alcohols in good yields after oxidation with H2O2 under basic conditions. The selective reduction of carboxylic acids with the evolved borane was examined. The organoboranes generated by the PV method successfully underwent Suzuki–Miyaura coupling. Using this PV system, reactions with borane can be carried out easily and safely in a common test tube.
From intermolecular interactions to texture in polycrystalline surfaces of 1,ω-alkanediols (ω = 10–13)
Luis-Raya, Gilgamesh,Ramírez-Cardona, Màrius,Luna-Bárcenas, Gabriel,Hernández-Landaverde, Martín A.,Jiménez-Nieto, Adair,García-Rivas, Jose Luis,Espa A-Sánchez, Beatriz Liliana,Sanchez, Isaac C.
, (2017/06/28)
Differences on herringbone molecular arrangement in two forms of long-chain 1,?-alkanediols (CnH2n+2O2 with n = 10, 11, 12, 13) are explained from the analysis of O-H···O hydrogen-bond sequences in infinite chains and the role of a C-H···O intramolecular hydrogen-bond in stabilization of a gauche defect, as well as the inter-grooving effectiveness on molecular packing. GIXD (Glancing Incidence X-ray Diffraction) experiments were conducted on polycrystalline monophasic samples. Diffracted intensities were treated with the multi-axial March-Dollase method to correlate energetic and geometrical features of molecular interactions with the crystalline morphology and textural pattern of samples. The monoclinic (P21/c, Z = 2) crystals of the even-numbered members (n = 10, 12; DEDOL and DODOL, respectively) are diametrical prisms with combined form {104}/{-104}/{001} and present a two-fold platelet-like preferred orientation, whereas orthorhombic (P212121, Z = 4) odd-numbered members (n = 11, 13; UNDOL and TRDOL, respectively) present a dominant needle-like orientation on direction [101] (fiber texture). We show that crystalline structures of medium complexity and their microstructures can be determined from rapid GIXD experiments from standard radiation, combined with molecular replacement procedure using crystal structures of compounds with higher chain lengths as reference data.
A highly active and air-stable ruthenium complex for the ambient temperature anti-markovnikov reductive hydration of terminal alkynes
Zeng, Mingshuo,Li, Le,Herzon, Seth B.
supporting information, p. 7058 - 7067 (2014/06/09)
The conversion of terminal alkynes to functionalized products by the direct addition of heteroatom-based nucleophiles is an important aim in catalysis. We report the design, synthesis, and mechanistic studies of the half-sandwich ruthenium complex 12, which is a highly active catalyst for the anti-Markovnikov reductive hydration of alkynes. The key design element of 12 involves a tridentate nitrogen-based ligand that contains a hemilabile 3-(dimethylamino) propyl substituent. Under neutral conditions, the dimethylamino substituent coordinates to the ruthenium center to generate an air-stable, 18-electron, κ3-complex. Mechanistic studies show that the dimethylamino substituent is partially dissociated from the ruthenium center (by protonation) in the reaction media, thereby generating a vacant coordination site for catalysis. These studies also show that this substituent increases hydrogenation activity by promoting activation of the reductant. At least three catalytic cycles, involving the decarboxylation of formic acid, hydration of the alkyne, and hydrogenation of the intermediate aldehyde, operate concurrently in reactions mediated by 12. A wide array of terminal alkynes are efficiently processed to linear alcohols using as little as 2 mol % of 12 at ambient temperature, and the complex 12 is stable for at least two weeks under air. The studies outlined herein establish 12 as the most active and practical catalyst for anti-Markovnikov reductive hydration discovered to date, define the structural parameters of 12 underlying its activity and stability, and delineate design strategies for synthesis of other multifunctional catalysts.
Temporal separation of catalytic activities allows anti-Markovnikov reductive functionalization of terminal alkynes
Li, Le,Herzon, Seth B.
, p. 22 - 27 (2014/01/17)
There is currently great interest in the development of multistep catalytic processes in which one or several catalysts act sequentially to rapidly build complex molecular structures. Many enzymes - often the inspiration for new synthetic transformations - are capable of processing a single substrate through a chain of discrete, mechanistically distinct catalytic steps. Here, we describe an approach to emulate the efficiency of these natural reaction cascades within a synthetic catalyst by the temporal separation of catalytic activities. In this approach, a single catalyst exhibits multiple catalytic activities sequentially, allowing for the efficient processing of a substrate through a cascade pathway. Application of this design strategy has led to the development of a method to effect the anti-Markovnikov (linear-selective) reductive functionalization of terminal alkynes. The strategy of temporal separation may facilitate the development of other efficient synthetic reaction cascades.
Regioselective reductive hydration of alkynes to form branched or linear alcohols
Li, Le,Herzon, Seth B.
supporting information, p. 17376 - 17379,4 (2020/09/16)
The regioselective reductive hydration of terminal alkynes using two complementary dual catalytic systems is described. Branched or linear alcohols are obtained in 75-96% yield with ?25:1 regioselectivity from the same starting materials. The method is compatible with terminal, di-, and trisubstituted alkenes. This reductive hydration constitutes a strategic surrogate to alkene oxyfunctionalization and may be of utility in multistep settings.
Regioselective ω-hydroxylation of medium-chain n-alkanes and primary alcohols by CYP153 enzymes from Mycobacterium marinum and Polaromonas sp. strain JS666
Scheps, Daniel,Honda Malca, Sumire,Hoffmann, Helen,Nestl, Bettina M.,Hauer, Bernhard
scheme or table, p. 6727 - 6733 (2011/11/30)
The oxofunctionalization of saturated hydrocarbons is an important goal in basic and applied chemistry. Biocatalysts like cytochrome P450 enzymes can introduce oxygen into a wide variety of molecules in a very selective manner, which can be used for the synthesis of fine and bulk chemicals. Cytochrome P450 enzymes from the CYP153A subfamily have been described as alkane hydroxylases with high terminal regioselectivity. Here we report the product yields resulting from C5-C12 alkane and alcohol oxidation catalyzed by CYP153A enzymes from Mycobacterium marinum (CYP153A16) and Polaromonas sp. (CYP153A P. sp.). For all reactions, byproduct formation is described in detail. Following cloning and expression in Escherichia coli, the activity of the purified monooxygenases was reconstituted with putidaredoxin (CamA) and putidaredoxin reductase (CamB). Although both enzyme systems yielded primary alcohols and α,ω-alkanediols, each one displayed a different oxidation pattern towards alkanes. For CYP153A P. sp. a predominant ω-hydroxylation activity was observed, while CYP153A16 possessed the ability to catalyze both ω-hydroxylation and α,ω- dihydroxylation reactions.
Dramatic switching of protein kinase C agonist/antagonist activity by modifying the 12-ester side chain of phorbol esters
Wada, Reiko,Suto, Yutaka,Kanai, Motomu,Shibasaki, Masakatsu
, p. 10658 - 10659 (2007/10/03)
A dramatic switching of PKC agonist and antagonist activity was observed by modification of the hydrophilicity of the 12-ester side chain of phorbol. Thus, phorbol ester 4 that contains a glycol at the 12-ester chain demonstrated a pure and significant antagonist ability of PKC; however, 3 that contains an alkanol at the 12-ester chain demonstrated a potent PKC agonist activity. On the basis of the structural difference between 3 and 4 and results of the partition assay in the Hela cell/PBS buffer system, we propose that 4 acts as a translocation poison of the PKC-phorbol ester complex. The approach of controlling the agonist/antagonist activity of phorbol esters by the nature (i.e., hydrophilicity, charge, and rigidity, etc.) of the 12-ester chain may be very useful for developing selective PKC inhibitors and a potential pharmaceutical compound for anticancer therapies. Copyright
Zirconium borohydride - A versatile reducing agent for the reduction of electrophilic and nucleophilic substrates
Narasimhan,Balakumar
, p. 4387 - 4395 (2007/10/03)
Zirconium borohydride, a potential reducing agent, reduces acids, esters, imines to the corresponding alcohols and secondary amines in good yield at room temperature within two hours. This facile reducing property was taken advantage off in the synthesis of pheromones and some novel chiral precursors for asymmetric synthesis.
Reduction of carboxylic acids by tetraalkyl ammonium borohydride
Narasimhan,Swarnalakshmi,Balakumar
, p. 941 - 946 (2007/10/03)
Tetraalkylammonium borohydride reduces carboxylic acids to the corresponding alcohols in good yields utilizing only stoichiometric quantities of hydride and also in the absence of any Lewis acids.
A simple alkene-catalyzed reduction of aromatic esters to alcohols by zinc borohydride
Narasimhan,Madhavan,Ganeshwar Prasad
, p. 385 - 390 (2007/10/03)
Reactivity of Zn(BH4)2 was modified by adding cyclohexene to achieve the reduction of aromatic esters to alcohols which reaction was not possible previously because of the mild nature of the reagent. Functional groups like Cl and nitro were tolerated.
