Lewis酸催化的不饱和醇羟基的活化

【作者】 黄文；

【导师】 周锡庚；

【作者基本信息】 复旦大学 ， 有机化学， 2009， 博士

【摘要】 本论文的工作主要是围绕Lewis酸对醇羟基的活化而展开的,全文主要分为四个部分:首先,探索了三氟甲磺酸基稀土配合物对烯丙醇羟基的活化作用,发现这类稀土配合物可以在温和条件下催化一些杂原子亲核试剂,如醇、硫醇、胺以及酰胺类化合物直接取代烯丙醇中羟基的反应,以良好到优秀的收率得到相应的烯丙基化产物。该反应具有化学选择性高、催化剂易于循环使用等特点。接下来,我们进行了稀土Lewis酸催化的烯丙醇和苄醇与活泼亚甲基的偶联反应研究,提供了一条有效的直接制备2-烷基1,3-二羰基化合物的方法。该反应的普适性良好,对于弱酸性的丙二酸二乙酯类化合物与烯丙醇的偶联也适用。进一步,我们发现二级炔丙醇在稀土金属三氟甲磺酸盐催化下也能很好地与1,3-二羰基化合物反应,给出其炔丙基化产物。然而,对于三级炔丙醇底物,在同样的反应条件下,反应给出的是异构化的联烯产物。此外,我们还深入研究了Yb（OTf）₃催化的烯丙醇以及炔丙醇与4-羟基香豆素的偶联反应。进一步,利用该反应为关键步骤,实现了一锅法合成具有生物活性骨架单元的多取代呋喃并香豆素化合物。随后,我们探索了三级炔丙醇的分子内烷基化反应。首先设计合成了一系列苄胺基取代的炔丙醇,发现在Lewis酸催化剂的存在下,这些取代炔丙醇能进行不寻常的串联醇羟基活化/异构化/分子内傅克烷基化反应,以中等至良好的收率给出相应的环化产物。首次实现了炔丙醇的分子内傅克烷基化反应,为直接一步合成多取代四氢异喹啉骨架化合物提供了一种有效的新方法。同时,在合适的条件下,一些四氢异喹啉产物还能进一步转化成二氢异喹啉衍生物,其中部分产物的结构得到了X-ray单晶衍射分析证明。最后,在研究酯基取代炔丙醇的分子内傅克反应中,发现一种非预期的多步串联环化反应,从而实现了从芳基取代炔丙醇到取代螺环或多环化合物的一步合成。同时还发现这种多步串联环化反应,可以通过改变反应条件以及催化剂,实现对反应中间体的选择性分离,并由此提出了可能的反应机理。此外,我们还考察了炔丙基位以及受体苯环上的电子效应、立体效应对反应的影响。进一步,我们对含MOM-以及EOM-取代的炔丙醇底物的分子内环化反应进行了研究,合成了一些具有生物活性骨架单元的氢化萘类化合物。更多还原

【Abstract】 This dissertation mainly focuses on the Lewis acid-catalyzed activation of hydroxy group in alcohols and some related reactions.The dissertation can be divided into four parts.Firstly,we have found that Yb（OTf）₃ can catalyze the direct substitution of the hydroxy group in allylic alcohols with a variety of heteroatom-centered nucleophiles, such as alcohols,thiols,amines and amides,to give the corresponding allylation products in good to excellent yields under mild reaction conditions.The advantages of current catalyst system are high chemistry selectivity and easy to recycle the catalyst.Secondly,we have investigated the coupling reaction of allylic alcohols and benzyl alcohols with active methylene compounds catalyzed by lanthanide Lewis acid,which provides an efficient route to synthesis of 2-alkyl-1,3-dicarbonyl compounds and are wide availability of the starting materials.It is noteworthy that the present catalyst is also high efficient for the direct hydroxy substitution of allylic alcohols with the acidic diethyl malonate.Furthermore,we have found that the Yb（OTf）₃-catalyzed reaction of secondary propargylic alcohols with 1,3-dicarbonyl compounds also proceeds smoothly to give the corresponding propargylation products.However,the treatment of tertiary propargylic alcohols with 1,3-dicarbonyl compounds gives the allenylation products under the same conditions.In addition,catalytic quantities of Yb（OTf）₃ can also effectively promote the propargylation and allylation of 4-hydroxycoumarins at the 3-position.By applying this reaction as the key step,a multi-substituted bioactive furocoumarin can easily be synthesized in a one-pot procedure.Thirdly,we have studied the intramolecular cyclization reaction of tertiary propargylic alcohols.We have designed and synthesized a variety of benzylamino-substituted propargylic alcohols.Treatment of these propargylic alcohols with 5 mol%of FeCl₃·6H₂O led to the occurrence of the tandem activation of hydroxy group/isomerization/cyclization reactions,giving tetrahydroisoquinolines in moderate to good yields,which provides a mild,versatile and efficient method for the one-step synthesis of substituted tetrahydroisoquinolines and represents the first example of the intramolecular Friedel-Crafts reaction of propargylic alcohols. Moreover,it was found that some substituted tetrahydroisoquinolines can be further transformed into dihydroisoquinoline derivatives under suitable conditions and the structures of some products have been further confirmed by X-ray single diffraction analysis.Finally,in the investigation on the intramolecular Friedel-Crafts reaction of ester-substituted propargylic alcohols,we have observed an unexpected tandem cyclization reaction that allows one-step synthesis of spirocyclics and polycycles. Significantly,the tandem cyclization is controllable,for which the dihydro-and tetrahydronaphthalene intermediates can be selectively isolated by changing the reaction conditions or catalyst.Based on this result,a reasonable mechanism for these reactions has been presented.Further investigation results demonstrate that chemoand regioselectivities of the second-step cyclization reaction strongly depends on the nature of substituents at the resulting ring and the nucleophilicity of the aryl rings.In addition,we have researched the intramolecular cyclization reactions of MOM-and EOM-substituted propargylic alchohols,and synthesized a variety of bioactive skeleton unit hydrogenated naphthalene compounds.更多还原