Ruthenium-Catalyzed (2 + 2) Intramolecular Cycloaddition of Allenenes
作者:Moisés Gulías、Alba Collado、Beatriz Trillo、Fernando López、Enrique Oñate、Miguel A. Esteruelas、José L. Mascareñas
DOI:10.1021/ja200784n
日期:2011.5.25
We report a ruthenium-catalyzed (2 + 2) intramolecularcycloaddition of allenes and alkenes. We have found that the use of the ruthenium complex RuH(2)Cl(2)(P(i)Pr(3))(2), which has previously gone unnoticed in catalytic applications, is crucial for the observed reactivity. The reaction proceeds under mild conditions and is fully diastereoselective, providing a practical entry to a variety of bicyclo[3
Metal-Triflate-Catalyzed Synthesis of Polycyclic Tertiary Alcohols by Cyclization of γ-Allenic Ketones
作者:Ilhem Diaf、Gilles Lemière、Elisabet Duñach
DOI:10.1002/anie.201310724
日期:2014.4.14
It has been established that bismuth(III) triflate catalyzes the cyclization of γ‐allenic ketones under mild reaction conditions. This reaction allows the selective formation of polycyclic tertiary alcohols from cyclic ketone derivatives. The resulting dienols can engage in stereoselective cycloadditions to efficiently afford complex polycyclic systems.
A series of nitrogen-tethered allenynes (‘5-aza-1,2-dien-7-ynes’) 1 were transformed to the corresponding 3-acyl-4-alkenylpyrrolidines 3 when treated with a catalytic amount of PtCl2 in MeOH at 70°. Initial Pt-promoted cyclization forms a nonclassical carbocationic intermediate. In contrast to the cycloisomerization in toluene, which produced the bicyclic cyclobutenes 2, the intermediate is intercepted
TfOH- and HBF<sub>4</sub>-Mediated Formal Cycloisomerizations and [4+3] Cycloadditions of Allene-alkynylbenzenes
作者:Yu Xiang、Zining Li、Lu-Ning Wang、Zhi-Xiang Yu
DOI:10.1021/acs.joc.8b00393
日期:2018.8.3
prepared allene-alkynylbenzenes to give pyrrolidines and cyclopentanes derivatives was developed. This reaction is initiated by the generation of allylic cation from allene, followed by alkyne’s reaction with the allylic cation, to give a vinylcation, which is finally intercepted by the triflate (TfO) anion. This cycloisomerization can be further tuned to become an acid-mediated intramolecular formal
Carbon−Carbon Bond Formation in Regio- and Stereoselective Palladium-Catalyzed Cyclization of Allene-Substituted Conjugated Dienes
作者:Joakim Löfstedt、Johan Franzén、Jan-E. Bäckvall
DOI:10.1021/jo0157324
日期:2001.11.1
Regio- and stereoselective palladium-catalyzed reactions of allene-substituted 1,3-dienes 1 in acetic acid at room temperature lead to cyclization with formation of a carbon-carbon bond between the middle carbon of the allene and the terminal carbon of the 1,3-diene. Two different types of reactions, both that constitute 1,4-carboacetoxylations of the 1,3-diene, have been developed. In one of the reactions