Ring-Opening Cyclization of Spirocyclopropanes Using Sulfoxonium Ylides
作者:Yuta Onuki、Hisanori Nambu、Takayuki Yakura
DOI:10.1248/cpb.c20-00132
日期:2020.5.1
cyclohexane-1,3-dione-2-spirocyclopropanes using dimethylsulfoxonium methylide proceeded regioselectively to produce 2,3,4,6,7,8-hexahydro-5H-1-benzopyran-5-ones in good to high yields. The reactions of cycloheptane- and cyclopentane-1,3-dione-2-spirocyclopropanes could construct [7.6]- and [5.6]-fused ring systems. This reaction was also carried out using sulfoxonium ethylide, butylide, and benzylide
Regioselective ring-opening cyclization of cyclohexane-1,3-dione-2-spirocyclopropanes with stabilized sulfoniumylides provided 2,3-trans-disubstituted 2,3,4,6,7,8-hexahydro-5H-1-benzopyran-5-ones in high yields without the formation of any isomers. The obtained product was readily converted into highly substituted chromane.
环己烷-1,3-二酮-2-螺环丙烷与稳定的硫鎓烷基化物的区域选择性开环环化提供了2,3-反式-二取代的2,3,4,6,7,8-六氢-5 H -1-苯并吡喃-高产率的5-ones,不形成任何异构体。所获得的产物易于转化为高度取代的苯并二氢吡喃。
Direct Oxidation of Cyclopropanated Cyclooctanes as a Synthetic Approach to Polycyclic Cyclopropyl Ketones
作者:Kseniya N. Sedenkova、Kristian S. Andriasov、Svetlana A. Stepanova、Igor P. Gloriozov、Yuri K. Grishin、Tamara S. Kuznetsova、Elena B. Averina
DOI:10.1002/ejoc.201701671
日期:2018.2.21
A series of polycyclic hydrocarbons containing cyclopropane moieties 1,2-annelated or spiro-condensed with cyclooctanering were investigated under oxidative conditions. Four oxidizing systems (O3 on SiO2, dioxirane derived from trifluoroacetone, CrO3 and RuO4, generated in situ), were employed to evaluate and compare their reactivity and usefulness. RuO4 was found to be the best one, considering its
An Efficient Method for the Synthesis of 2′,3′-Nonsubstituted Cycloalkane-1,3-dione-2-spirocyclopropanes Using (2-Bromoethyl)diphenylsulfonium Trifluoromethanesulfonate
An efficient and practical synthesis of 2',3'-nonsubstituted cyclohexane-1,3-dione-2-spirocyclopropanes using a sulfonium salt was achieved. The reaction of 1,3-cyclohexanediones and (2-bromoethyl)diphenylsulfonium trifluoromethanesulfonate with powdered K2CO3 in EtOAc at room temperature (r.t.) provided the corresponding spirocyclopropanes in high yields. The synthetic method was also applied to 1
The ring‐opening cyclization of 2′,3′‐nonsubstituted and 2′‐electron‐withdrawing group (EWG)‐substituted cyclohexane‐1,3‐dione‐2‐spirocyclopropanes was accomplished using iodide as a catalyst. The nonsubstituted derivatives afforded 3,5,6,7‐tetrahydro‐1‐benzofuran‐4(2H)‐ones in high yields in the presence of trimethylsilyl iodide at room temperature. The EWG‐substituted spirocyclopropanes, in turn, underwent