2009-83-8Relevant articles and documents
Method for synthesizing 6-chloro-1-hexanol by taking 1,6-hexanediol and cyanuric chloride as raw materials
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Paragraph 0035-0062, (2021/01/29)
The invention relates to the field of organic synthesis, and discloses a method for synthesizing 6-chloro-1-hexanol by using 1,6-hexanediol and cyanuric chloride as raw materials, wherein the method comprises the following steps: 1) dissolving cyanuric chloride in a solvent A, stirring to react, and obtaining a solution for later use after the reaction is finished; 2) preparing 1,6-hexanediol or asolution thereof; 3) slowly dropwise adding the solution obtained in the step (1) into the 1,6-hexanediol or the solution thereof obtained in the step (2), carrying out heat preservation reaction after dropwise adding is finished, filtering reaction liquid after the reaction is finished, rinsing a filter cake by using a solvent B, and collecting filtrate; 4) rectifying the filtrate obtained in the step 3 to prepare the finished product. According to the method, 1,6-hexanediol and cyanuric chloride are used as raw materials to synthesize 6-chloro-1-hexanol, the raw materials are cheap and easyto obtain, the purity of the obtained product can reach 99% or above, the yield can reach 95% or above, the reaction condition is mild, aftertreatment is simple, and the method is more suitable for large-scale industrial application.
Chemoselective Cleavage of Si-C(sp3) Bonds in Unactivated Tetraalkylsilanes Using Iodine Tris(trifluoroacetate)
Matsuoka, Keitaro,Komami, Narumi,Kojima, Masahiro,Mita, Tsuyoshi,Suzuki, Kimichi,Maeda, Satoshi,Yoshino, Tatsuhiko,Matsunaga, Shigeki
supporting information, p. 103 - 108 (2021/01/13)
Organosilanes are synthetically useful reagents and precursors in organic chemistry. However, the typical inertness of unactivated Si-C(sp3) bonds under conventional reaction conditions has hampered the application of simple tetraalkylsilanes in organic synthesis. Herein we report the chemoselective cleavage of Si-C(sp3) bonds of unactivated tetraalkylsilanes using iodine tris(trifluoroacetate). The reaction proceeds smoothly under mild conditions (-50 °C to room temperature) and tolerates various polar functional groups, thus enabling subsequent Tamao-Fleming oxidation to provide the corresponding alcohols. NMR experiments and density functional theory calculations on the reaction indicate that the transfer of alkyl groups from Si to the I(III) center and the formation of the Si-O bond proceed concertedly to afford an alkyl-λ3-iodane and silyl trifluoroacetate. The developed method enables the use of unactivated tetraalkylsilanes as highly stable synthetic precursors.
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.
Oxidation of monohydric and dihydric alcohols with CCl4 catalyzed by molybdenum compounds
Khusnutdinov,Shchadneva,Burangulova,Muslimov,Dzhemilev
, p. 1615 - 1621 (2007/10/03)
Mo(CO)6 catalyzed oxidation of alcohols and diols with tetrachloromethane. Primary oxidation products in reaction of alcohols with CCl4 are alkyl hypochlorites, and final products depending on the structure of initial alcohol are aldehydes (as acetals), ketones, chloroketones, and esters.
Efficient method for the deprotection of tert-butyldimethylsilyl ethers with TiCl4-Lewis base complexes: Application to the synthesis of 1β-methylcarbapenems
Iida, Akira,Okazaki, Hiroki,Misaki, Tomonori,Sunagawa, Makoto,Sasaki, Akira,Tanabe, Yoo
, p. 5380 - 5383 (2007/10/03)
TiCl4-Lewis base (AcOEt, CH3NO2) complexes smoothly deprotected tert-butyldimethylsilyl (TBDMS) ethers. The reaction velocity with these complexes, which seemed less reactive due to the influence of Lewis bases, was considerably greater than that with TiCl4 alone. Selective desilylations between aliphatic and aromatic TBDMS ethers (1 and 5), between 1 and benzyl, allyl, tosyl, methoxyphenyl, and chloroacetyl ethers (13, 14, 15, 16, and 17), and between TBDMS and TBDPS ethers (18 and 19) were successfully performed. Desilylation of TBDMS-aldol, acyloin, and β-lactam analogues 9-12 proceeded smoothly due to anchimeric assistance by the neighboring carbonyl groups. The present method was successfully applied to the practical synthesis of 1β-methylcarbapenems 20a′-f′.
Process for the preparation of α-bromo, ω-chloroalkanes
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, (2008/06/13)
Described is a process for easily preparing an α-bromo,ω-chloroalkane which is high in purity represented by the formula: Br(CH2)n Cl in which n stands for an integer of 4 to 12. The process comprises reacting in an organic solvent an α,ω-dichloroalkane with an αω-dibromoalkane. As the organic solvent, an aprotic nitrogen-containing or sulfur-containing organic solvent having a dielectric constant at 20° C. of 20 or larger, for example, N,N-dimethylformamide, N,N-dimethylacetamide or N,N-dimethylimidazolidinone is preferred.
Chemoselective oxidation of organozine reagents with oxygen
Klement, Ingo,Luetjens, Henning,Knochel, Paul
, p. 9135 - 9144 (2007/10/03)
Functionalized organozinc compounds prepared by hydrozincation, carbozincation or by boron-zinc exchange can be directly oxidized in a selective manner to the corresponding functionalized alcohols or hydroperoxides depending on the reaction conditions.
Oxidation of zinc organometallics prepared by hydrozincation or carbozincation using oxygen
Klement, Ingo,Luetjens, Henning,Knochel, Paul
, p. 3161 - 3164 (2007/10/02)
Organozinc compounds prepared by the hydrozincation or carbazincation of functionalized unsaturated molecules can be directly oxidized by oxygen affording alcohols after reductive workup in satisfactory yields.
