40894-17-5Relevant academic research and scientific papers
Synthesis of 1,3-Amino Alcohols, 1,3-Diols, Amines, and Carboxylic Acids from Terminal Alkynes
Zeng, Mingshuo,Herzon, Seth B.
, p. 8604 - 8618 (2015/09/15)
The half-sandwich ruthenium complexes 1-3 activate terminal alkynes toward anti-Markovnikov hydration and reductive hydration under mild conditions. These reactions are believed to proceed via addition of water to metal vinylidene intermediates (4). The functionalization of propargylic alcohols by metal vinylidene pathways is challenging owing to decomposition of the starting material and catalytic intermediates. Here we show that catalyst 2 can be employed to convert propargylic alcohols to 1,3-diols in high yield and with retention of stereochemistry at the propargylic position. The method is also amenable to propargylic amine derivatives, thereby establishing a route to enantioenriched 1,3-amino alcohol products. We also report the development of formal anti-Markovnikov reductive amination and oxidative hydration reactions to access linear amines and carboxylic acids, respectively, from terminal alkynes. This chemistry expands the scope of products that can be prepared from terminal alkynes by practical and high-yielding metal-catalyzed methods.
Synthesis of oxazolidin-2-ones and imidazolidin-2-ones directly from 1,3-diols or 3-amino alcohols using iodobenzene dichloride and sodium azide
He, Tian,Gao, Wen-Chao,Wang, Wei-Kun,Zhang, Chi
, p. 1113 - 1118 (2014/04/03)
A general and efficient method for the synthesis of oxazolidin-2-ones and imidazolidin-2-ones directly from 1,3-diols and 3-amino alcohols has been developed using the same reagent combination of iodobenzene dichloride (PhICl2) and sodium azide (NaN3).
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.
A new approach to the synthesis of 1-oxaspiro[4.n]alkanes and tetrahydrofurans by the 1,5-CH insertion reaction of magnesium carbenoids
Satoh, Tsuyoshi,Yasoshima, Tsukasa,Momochi, Hitoshi
scheme or table, p. 2074 - 2077 (2012/07/14)
1-Alkoxy-1-[2-chloro-2-(p-tolylsulfinyl)ethyl]cycloalkanes were prepared from various cyclic ketones in good overall yields. Treatment of these cycloalkanes bearing a sulfinyl group with i-PrMgCl resulted in the formation of 1-oxaspiro[4.n]alkanes in high to quantitative yields via the 1,5-CH insertion reaction of generated magnesium carbenoid intermediates. When this procedure was commenced with acyclic ketones, multi-substituted tetrahydrofurans were obtained in up to a 96% yield. This procedure provides a new and good way for the synthesis of 1-oxaspiro[4.n]alkanes and tetrahydrofurans with the formation of a carbon-carbon bond between a carbenoid carbon and a non-activated carbon in high yields. The oxygen atom in the magnesium carbenoid intermediates was proved to act very important roles in the 1,5-CH insertion reaction.
1,3-Diol synthesis via controlled, radical-mediated C-H functionalization
Chen, Ke,Richter, Jeremy M.,Baran, Phil S.
, p. 7247 - 7249 (2008/12/21)
The invention of a method for the synthesis of 1,3-diols from the corresponding alcohols is described, via controlled, radical-mediated C-H functionalization. The sequence described herein entails near quantitative conversion to the corresponding trifluoroethyl carbamate, followed by a variant of the Hofmann-Loffler-Freytag reaction, cyclization, and hydrolysis to provide the 1,3-diols. In addition to the 10 examples presented herein, the syntheses of four natural products are facilitated by this directed oxyfunctionalization. This methodology is demonstrated to be orthogonal to other known C-H oxidations. Finally, this sequence is efficient, practical, inexpensive, and scalable. Copyright
Methane formation by reaction of a methyl thioether with a photo-excited nickel thiolate - A process mimicking methanogenesis in archaea
Signor, Luca,Knuppe, Carola,Hug, Robert,Schweizer, Bernd,Pfaltz, Andreas,Jaun, Bernhard
, p. 3508 - 3516 (2007/10/03)
The formation of a sulfuranyl radical intermediate followed by methyl transfer to the nickel(I) center of coenzyme F430 and generation of the disulfide has been proposed as a possible mechanism for the formation of methane catalyzed by methyl coenzyme M r
Vitamin D analogues
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, (2008/06/13)
STR1 The present invention relates to compounds of formula (I), in which formula, n is an integer from 1-7; and R1 and R2, which may be the same or different, stand for hydrogen, or lower alkyl (but with the proviso that when n=1, R1 and R2 cannot simultaneously be hydrogen, nor can R1 and R2 simultaneously be an alkyl group independently chosen from methyl, ethyl and normal-propyl, and when n=2, R1 and R2 cannot simultaneously be methyl), or lower cyclo-alkyl, or, taken together with the carbon (starred in formula I) bearing the hydroxyl group, R1 and R2 can form a saturated or unsaturated C3 -C9 carbocyclic ring; and R3 and R4 represent either simultaneously hydrogen, or when taken together constitute a bond, such that a double bond connects carbons 22 and 23; including diastereoisomeric forms (e.g. E or Z configuration of the 22,23-double bond; R or S configuration at the starred carbona atom) of the compounds of formula (I), in pure form or in mixtures. The present compounds find use in both the human and veterinary practice and show antiinflammatory and immuno-modulating effects as well as strong activity in inducing differentiation and inhibiting undesirable proliferation of certain cells, including cancer cells and skin cells.
Synthetic applications of glycidic thiolesters. Regioselective reduction to 1,3-diols and 2,3-epoxy alcohols
Liu, Hsing-Jang,Luo, Weide
, p. 128 - 134 (2007/10/02)
Glycidic thiolesters were shown to undergo regioselective reduction with Raney nickel to give 1,3-diols.With sodium borohydride at room temperature and lithium aluminum hydride at -78 deg C, the reduction of glycidic thiolesters was found to proceed chemo
Synthetically Useful β-Lithioalkoxides from Reductive Lithiation of Epoxides by Aromatic Radical Anions
Cohen, Theodore,Jeong, In-Howa,Mudryk, Boguslaw,Bhupathy, M.,Awad, Mohamed M. A.
, p. 1528 - 1536 (2007/10/02)
Epoxides are reductively cleaved by means of lithium 4,4'-di-tert-butylbiphenylide.Ethylene oxide itself cleaves to lithium 2-lithioethoxide (15) in less than 5 min at -95 deg C.Epoxides possessing one unsubstituted carbon atom reduce in a matter of minutes at -78 deg C.When both carbon atoms are monosubstituted, at least 1 h is required.Epoxides with one or with two geminal saturated substituents open mainly between the oxygen atom and the least substituted carbon atom.Ring opening in the other direction leads to an unstable β-lithioalkoxide which very rapidly forms an olefin.Acyclic 1,2-disubstituted epoxides yield only olefins.Cyclooctene oxide produces, after protonation, a 3:7 ratio of cyclooctanol and cyclooctene.Cyclohexene oxide gives a 3:1 ratio of cyclohexanol and cyclohexene.Vinyloxiranes, on the other hand, open at the most substituted C-O bond to produce an allylic anion associated with an alkoxide.The carbanionic centers of the resulting dianions add to the carbonyl groups of aldehydes and ketones; however, when a hydrogen atom is present on the carbon atom which is attached to both negatively charged atoms, some reduction of the carbonyl group competes with the nucleophilic addition.The allylic anions derived from vinyloxiranes, after treatment with titanium tetraisopropoxide or cerium(III) chloride, add to aldehydes mainly at the most or least substituted terminus, respectively.In the former case, the configuration of the resulting glycols is predominantly anti.A number of adducts of the dianions with conjugated unsaturated aldehydes and ketones can be converted to unsaturated cyclic 6-membered ring ethers in the presence of acid or methanesulfonyl chloride.
