锡存在下取代的炔丙基溴与醛反应的选择性

报道三甲基硅基和苯基取代的炔丙基溴在锡存在下与醛的反应, 并讨论了反应的选择性。三甲基硅基炔丙基溴与醛的反应产率约为71-84%。产物中丙二烯醇与高炔丙基醇之比在44 :56到25 : 75之间, 苯基炔丙基溴的反应得到了产物丙二烯醇。     

锡-铟促进和微波辐射辅助下醛和炔丙基溴的炔丙基化反应

A rapid and regioselective preparation of homopropargyl alcohols was reported. In the presence of SnCl2C6HsMe3NBr and microwave irradiation, the mixture of tin-indium and propargyl bromide reacted quickly with aldehydes in aqueous media to produce the homopropargyl alcohols exclusively in high yields. For benzaldehydes bearing different substituents, electronic effect of the substituents affected the reaction, the electron-withdrawing groups promoting the reaction and the electron-donating groups impeding the reaction. The reactions of benzaldehydes bearing an ortho substituent group on the phenyl ring with propargyl bromide may yield a mixture of regioisomers （homopropargyl and homoallenyl alcohols） or a single homoallenic alcohol due to the steric effect.     

高烯丙基醇和高炔丙基醇的无溶剂合成

在活化锌粉的促进下,通过羰基化合物的烯丙基化和炔丙基化反应,实现了高烯丙基醇和高炔丙基醇的快速无溶剂合成,收率72％～88％。产物的结构经1^H NMR,MS和元素分析确证。     

金属单质锡促进的水相中醛的Barbier类型炔丙基化反应

报道了一种简单、 高效且快速的醛的炔丙基化反应体系. 使用廉价的金属单质锡粉, 在路易斯酸SnCl₂·2H₂O促进下, 实现了水相中醛羰基化合物的Barbier类型炔丙基化反应, 高收率、高区域选择性地得到单一的高炔丙基醇产物(收率99%). 该方法具有底物适用范围广、反应条件温和(30℃)、环境友好(以水为介质)及反应速度快(30 min内反应原料基本消失)等优点. 另外, 在使用肉桂醛为底物且将反应温度升至55℃时, 意外地得到了中等收率的新型高度对称的烯炔醚化合物.     

金属锡作用下炔丙基碘与醛类化合物的反应

金属锡作用下的烯丙基卤代物与羰基化合物的加成反应以其反应条件温和及能选择性地与含有其他反应活性基团的羰基化合物加成等特点而显示出在有机合成上的应用价值。但目前这类反应还只局限于烯丙基卤代物反应的范围内。本文首次报道金属锡作用下的炔丙     

Cu催化吲哚啉的炔丙基烷基化/脱氢对映选择性合成手性N-炔丙基吲哚化合物(英文)

基于吲哚啉的Cu催化不对称炔丙基烷基化及DDQ脱氢策略,成功合成了手性N-炔丙基吲哚化合物.通过使用一个结构刚性的酮亚胺三齿P,N,N-配体,反应获得了很好的对映选择性.该方法反应条件温和、底物适用范围广、产物收率高、立体选择性好,为手性N-炔丙基吲哚化合物的合成提供了一条简捷、高效的新途径.     

Enantioselective carbonyl propargylation by iridium-catalyzed transfer hydrogenative coupling of alcohols and propargyl chlorides

It takes alkynes! Exposure of propargyl chlorides to primary benzylic alcohols in the presence of [Ir(cod){(R)-segphos}]OTf (cod = 1,5-cyclooctadiene, segphos = 5,5'-bis(diphenylphosphino)-4,4'-bi-1,3-benzodioxole, Tf = trifluoromethanesulfonyl) results in hydrogen exchange to give allenyliridium-aldehyde pairs that combine to form products of propargylation with high ee?value (see scheme). The reaction can also be conducted using aldehydes.     

Reactions of dysprosium diiodide with phenyl-and pentafluorophenylgermanium compounds

Reactions of DyI₂ with (C₆F₅)₃GeH, (C₆F₅)₃GeBr, and (C₆F₅)₂GeBr₂ gave rise to the hyperbranched polymer [(C₆F₅)₂Ge(C₆F₄)]_n (4) in 22% to 65.7 yields. The major product of the reaction with (C₆F₅)₃GeBr was perfluorinated hexaphenyldigermane in 61% yield. Under the same conditions, the germylmercury compound [(C₆F₅)₃Ge]₂Hg yielded the ionic complex { [(C₆F₅)₃Ge]₃Hg}⁻[DyI₂]⁺. Hexaphenyldigermane slowly reacted with DyI₂ even at elevated temperature to give polymer 4 in 8% yield. Perfluorinated tetraphenylgermane and nonfluorinated phenylgermanes Ph₃GeH, Ph₃GeGePh₃, and (Ph₃Ge)₂O did not react with DyI₂ but they initiated its reaction with THF. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2428–2432, November, 2005.     

Metallic dysprosium promoted allylation of carbonyl compounds in the presence of mercuric chloride

Dysprosium metal promoted Barbier-type allylation of ketones and aldehydes has been investigated. It has been shown that dysprosium metal (activated by mercuric chloride) is effective in promoting the reaction of ketones with allyl iodide. The corresponding homoallylic alcohols are obtained in satisfactory yields. This reaction is regioselective and chemoselective. An α , β -unsaturated ketone affords a 1,2-addition product selectively. Reactive groups (such as Cl, Br, and methoxy) of aromatic ketones remain unchanged under the reaction conditions. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:475–478, 1998     

One-pot, solvent-free regioselective addition reactions of propargyl bromide to carbonyl compounds mediated by Zn-Cu couple

A Barbier-type propargylation of carbonyl compounds with propargyl bromide has been achieved with reactive zinc-copper couple under solvent-free conditions. The reaction of aldehydes with propargyl bromide produced the unique homopropargyl alcohols in excellent yields at room temperature without the formation of homoallenyl alcohols. The ketones reacted with propargyl bromide to give the corresponding homopropargyl alcohols in good to excellent yields at −14 to −16 °C. The advantages of this method are excellent yields, short reaction time, high regioselectivity, and avoidance of the use of organic solvents.     

钐试剂在合成中的应用I. 金属钐作用下烯丙基和苄基卤代物与羰基化合物的反应

本文研究了金属钐作用下的Barbier型反应。结果表明, 经氯化汞活化的金属钐对酮类化合物与烯丙基或苄基卤代物的反应很有效, 可高产率地生成叔醇。此反应有很好的区位选择性和化学选择性, 与α, β-不饱和酮的反应未发现1, 4-加成产物生成, 与环上有卤素(Br, Cl)取代的芳香酮反应, 取代基不受影响。产物的形成可能通过了有机钐中间体。     

Regioselective synthesis of linalyl compounds via addition reaction of geranyl bromide and tin with carbonyl compounds

Linalyl alkyl or aryl carbinols were regioselectively synthesized by the reaction ofgeranyl bromide and powdered tin with aldehydes and ketones.     

Highly selective deblocking of propargyl carbonates in the presence of propargyl carbamates with tetrathiomolybdate

Propargyloxycarbonyl chloride, 1, has been used to protect the hydroxyl and amino functionalities of amino alcohols and aminophenols in one pot using triethylamine or pyridine as a base. The increased reactivity of benzyltriethylammonium tetrathiomolybdate, 2, toward propargyl carbonates over propargyl carbamates is studied in detail and has been exploited further to develop an orthogonal protection strategy for the hydroxyl and amino functionalities. For example, 2-amino-1-butanol, 6a, was treated with 1 to get the N,O-diPoc compound 7a in 90% yield, which when treated with 1.1 equiv of 2 at room temperature removes the Poc group attached to oxygen while leaving the one attached to nitrogen intact to yield compound 8a in 85% yield. This particular observation offers a new protecting strategy where an amine and an alcohol group can be protected simultaneously in one pot, and in a later synthetic step, if the alcohol group has to be deprotected selectively, it can be achieved with 1 equiv of 2.     

Hydrogen-transfer reduction of carbonyl compounds promoted by nickel nanoparticles

Nickel(0) nanoparticles, generated from nickel(II) chloride, lithium powder and a catalytic amount of 4,4-di-tert-butylbiphenyl (DTBB) in THF at room temperature, have been found to promote the reduction of a variety of ketones and aldehydes by transfer hydrogenation using isopropanol as the hydrogen donor. The nickel nanoparticles were characterised and could be re-utilised with a good performance in the absence of a base. A mechanistic study demonstrates that the reaction proceeds through a dihydride-type mechanism.     

三碘化铝促进的α-溴代酮与羰基化合物的Aldol反应

在现场制备的三碘化铝促进下，α-溴代酮与羰基化合物发生脱溴的Aldol反应以中等到良好的产率生成β-羟基酮，这一反应也表现出很高的syn选择性。