Activation of Mononuclear Arene Ruthenium Complexes for Catalytic Propargylation Directly with Propargyl Alcohols
作者:Emilio Bustelo、Pierre H. Dixneuf
DOI:10.1002/adsc.200600512
日期:2007.4.2
ligand. The in situ generated catalyst has been applied to catalytic transformations of alkynes and propargylic alcohols: propargylation of furans, propargyl ether synthesis from internal and terminal propargylic alcohols with propargyl, homopropargyl and allyl alcohols, selective dimerization of phenylacetylene into E-enyne, and propargyl alcohol rearrangement into α,β-unsaturated aldehydes and ketones
[(对伞花基)RuX(CO)(PR 3)] [OTf](R = Ph,Cy; X = Cl,OTf)类型的单核络合物促进呋喃与炔丙醇的直接催化炔丙基化。这些前体是通过活化炔丙醇从[(对-cymene)RuCl(OTf)(PR 3)]原位产生的,导致经由亚烯基和烯基-羟基卡宾中间体形成羰基配体。催化活性物质的产生需要短的初始热活化以诱导对-异丙基配体的去配位。在原位生成的催化剂已用于炔烃和炔丙醇的催化转化:呋喃的炔丙基化,内部和末端炔丙醇与炔丙基,高炔丙基和烯丙基醇的炔丙基醚合成,苯乙炔的选择性二聚为E-烯炔和炔丙醇重排为α ,β-不饱和醛和酮通过Meyer-Schuster重排。含有内部CC键的炔丙醇的炔丙基化表明通过Nicholas型中间体(金属稳定的炔丙基阳离子)的活化。
Synthesis of Cyclic <i>cis</i>-Enediynes from Manganese Carbyne Complexes and α,ω-Diynes
作者:Charles P. Casey、Trevor L. Dzwiniel、Stefan Kraft、Ilia A. Guzei
DOI:10.1021/om0303799
日期:2003.9.1
Cyclic cis-enediynes are readily prepared by a two-step one-pot procedure. The first step is the copper-catalyzed addition of alpha,omega-diynes to manganese carbyne complexes to give intermediate bis(alkynylcarbene) complexes that rearrange to enediyne complexes below room temperature. In the second step, the free enediyne is released from manganese by photolysis, copper-catalyzed air oxidation, or stoichiometric Cu(II) oxidation. These new procedures have been applied to a variety of five-, six-, and seven-membered-ring cyclic enediynes containing a range of ether, ester, and ketone functional groups.
Lewis Acid-Catalyzed Propargylic Etherification and Sulfanylation from Alcohols in MeNO2-H2O
Direct scandium- and lanthanum-catalyzed etherifications of propargyl alcohols 1 and 6 in MeNO2–H2O provided propargyl ethers 3, 4 and 7 in high yields. In addition, reactions of 1 and 6 with thiols exclusively yielded the corresponding propargyl sulfides.