An efficient synthesis of cycloalkane-1,3-dione-2-spirocyclopropanes from 1,3-cycloalkanediones using (1-aryl-2-bromoethyl)-dimethylsulfonium bromides: application to a one-pot synthesis of tetrahydroindol-4(5H)-one
摘要:
An efficient synthesis of cyclohexane- and cyclopentane-1,3-dione-2-spirocyclopropanes from 1,3-cycloalkanediones using sulfonium salts was achieved. The reaction of 1,3-cycloalkanediones with (1-aryl-2-bromoethyl)-dimethylsulfonium bromides and powdered K2CO3 in EtOAc provided the corresponding spirocyclopropanes in high yields. Furthermore, a one-pot synthesis of tetrahydroindol-4(5H)-one from 1,3-cyclohexanedione was achieved using the present protocol and a sequential ring-opening cyclization of spirocyclopropane with a primary amine. (c) 2015 Elsevier Ltd. All rights reserved.
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。
Ring‐Opening Cyclization of Spirocyclopropanes with Stabilized Phosphorus Ylides: Access to Indane and Azulene Skeletons
In this study, regio- and diastereoselective ring-opening cyclization of spirocyclopropanes with phosphorus ylides stabilized by electron-withdrawing groups were developed. The reaction of various cyclohexane-1,3-dione-2-spirocyclopropanes with phosphorus ylides bearing alkoxycarbonyl groups proceeded smoothly without any additives to provide the corresponding 6,7-dihydroindan-4-ones in 32–87% yields