TfOH-catalyzed tandem cyclopropane ring enlargement/C–C formation/etherification of alkynylcyclopropanes and 1,3-diketones to cyclobutane-fused dihydrofurans
作者:Siyu Ye、Zhi-Xiang Yu
DOI:10.1039/c0cc04283h
日期:——
A new type of TfOH-catalyzed tandem cyclopropane ring enlargement/CâC formation/etherification reaction between alkynylcyclopropanes and 1,3-diketones to cyclobutane-fused dihydrofurans is described. The reaction tolerates a range of aryl and alkyl substituents with moderate to good yields.
of the soft acidic noble metal catalyst and affords products featuring an additional versatile CI bond. Similar strategies for replacing ynophilic cationic gold(I) complexes in oxidative goldcatalysis with likewise ynophilic stoichiometric electrophiles would enable the development of new synthetic methods.
Fe-catalyzed highly selective ring expansion of alkynylcyclopropyl alkanols to cyclobutanols
作者:Anjun Chen、Riyuan Lin、Qingjian Liu、Ning Jiao
DOI:10.1039/b916623h
日期:——
A Fe-catalytic highly selective ring expansion reaction of alkynylcyclopropyl alkanols to alkynylcyclobutanols via a 1,2-carbon shift under mild conditions was developed. A new class of homogeneous FeCl2/O2 catalytic system was employed in these novel transformations.
A heterogeneous gold(I)-catalyzed ring expansion of unactivated alkynylcyclopropanes with sulfonamides leading to (E)-2-alkylidenecyclobutanamines
作者:Feiyan Yi、Bin Huang、Quan Nie、Mingzhong Cai
DOI:10.1016/j.tetlet.2016.08.062
日期:2016.9
A heterogeneous gold(I)-catalyzed ringexpansion of unactivated alkynylcyclopropanes was achieved in 1,2-dichloroethane at 100 °C in the presence of sulfonamides by using a magnetic nanoparticle-supported phosphine gold(I) complex [Fe3O4@SiO2-P-AuOTf] as catalyst, yielding a variety of (E)-2-alkylidenecyclobutanamines in moderate to high yields. The new heterogeneous gold catalyst can easily be separated
通过使用磁性纳米粒子负载的膦金(I)络合物[Fe 3 O 4 @SiO] ,在磺酰胺存在下,在1,2-二氯乙烷中,在1,2-二氯乙烷中,未活化的炔基环丙烷在非均相的金(I)催化下扩环。2 -P-AuOTf]作为催化剂,以中等至高产率产生各种(E)-2-亚烷基亚环丁胺。通过施加外部磁体,可以轻松地从反应混合物中分离出新的多相金催化剂,并循环至少10次,而不会显着降低活性。
Gold(I)-Catalyzed Ring Expansions of Unactivated Alkynylcyclopropanes to (<i>E</i>)-2-Alkylidenecyclobutanamines in the Presence of Sulfonamides
作者:Siyu Ye、Zhi-Xiang Yu
DOI:10.1021/ol9028786
日期:2010.2.19
The ringexpansion of cyclopropane derivatives provides a powerful method to construct synthetically useful four-membered carbocycles. Herein, a new type of gold(I)-catalyzed ringexpansion of an unactivated alkynylcyclopropane/sulfonamide trapping strategy to (E)-2-alkylidenecyclobutanamines was described. The reaction tolerates a range of aryl and alkyl substituents with moderate to good yields.