Alkyne versus allene activation in platinum- and gold-catalyzed cycloisomerization of hydroxylated 1,5-allenynes.
Alkyne versus allene activation in platinum- and gold-catalyzed cycloisomerization of hydroxylated 1,5-allenynes.
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羟基化 1,5-丙炔的铂和金催化环异构化中炔烃与丙二烯的活化。
DOI：
10.1002/chem.200701522
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
M. Malacria
中科院分区：
文献类型：
--
作者：
Riadh Zriba;V. Gandon;C. Aubert;L. Fensterbank;M. Malacria
3-羟基-1,5-烯炔1的化学和立体选择性转化已经实现了多种新的和潜在有用的环化合物。在炔部分含有硅基的底物经过纯热或路易斯酸催化的醛烯型转化为2-亚甲基-3-乙烯基环戊烯-3-烯醇衍生物2。当在催化量的PtCl(2)或PtCl(4)存在下加热时，这些初始环戊烯醇可以进一步转化为3-乙烯基环戊烯-2-烯酮3。另一方面，烷基取代的3-羟基-1,5-烯炔在回流条件下是稳定的。然而，PtCl(2)和PtCl(4)可以选择性地激活这些底物的炔部分，使其受到内部烯双键的分子内亲核攻击，从而产生前所未有的6-亚甲基双环[3.1.0]己烷-3- 1衍生物4。在金基催化剂的作用下，假设反应在二氯甲烷中进行，Au(I)和Au（III）配合物选择性地激活底物的烯片段，使羟基在分子内亲核攻击，生成2-乙基-3,6-二氢- 2h -吡喃5。如果反应在甲苯中进行，也可以与Au(I)和Au（III）配合物形成4型化合物。对这些新化合物的反应性进行了部分研究，并在温和条件下氧化或金催化的环异构化反应得到了多环酮。
Chemo- and stereoselective transformations of 3-hydroxy-1,5-allenynes 1 into a variety of new and potentially useful cyclic compounds have been achieved. Substrates bearing a silyl group at the alkyne moiety undergo purely thermal or Lewis acid catalyzed Alder-ene type transformations into 2-methylene-3-vinylcyclopent-3-enol derivatives 2. When heated in the presence of a catalytic amount of PtCl(2) or PtCl(4), these incipient cyclopentenols could be further transformed into 3-vinylcyclopent-2-enones 3. On the other hand, alkyl-substituted 3-hydroxy-1,5-allenynes proved to be stable under refluxing conditions. Nevertheless, PtCl(2) and PtCl(4) could selectively activate the alkyne moiety of these substrates toward intramolecular nucleophilic attack of the internal allene double bond to yield unprecedented 6-methylenebicyclo[3.1.0]hexan-3-one derivatives 4. With gold-based catalysts, provided that the reaction is carried out in dichloromethane, both Au(I) and Au(III) complexes selectively activate the allene fragment of the substrates toward intramolecular nucleophilic attack of the hydroxyl group to yield 2-ethynyl-3,6-dihydro-2H-pyrans 5. Compounds of type 4 can also be formed with Au(I) and Au(III) complexes if the reaction is carried out in toluene. The reactivity of these new compounds has been partially investigated, and polycyclic ketones were obtained after oxidation under mild conditions or gold-catalyzed cycloisomerization.
影响因子：
15
作者：
Brummond, KM;Chen, HF;You, LF
通讯作者：
You, LF