Oxyallyl cation promoted dearomative semipinacol rearrangement: a facile stereodivergent synthesis of spiro-indolines with contiguous quaternary centers
作者:Yu-Yang Xie、Yun-Peng Wang、Xiao-Jing Zhao、Ai-Fang Wang、Zhi-Min Chen、Yong-Qiang Tu
DOI:10.1039/d1cc02033a
日期:——
indole-type allylic alcohols was disclosed for the stereodivergent synthesis of spiro-indolines. A variety of spiro-indolines were obtained with moderate to good yields. Three contiguous stereocenters, two of which are vicinal quaternary centers, were effectively formed with good diastereoselectivity. It is worth noting that two diastereoisomers of rearranged products can be readily achieved by easily regulating
A concise, simple two-step method for the preparation of [4+3] cycloadducts from ketones using Koser"s reagent and trifluoroethanol-triethylamine has been developed. This sequence affords yields similar to those obtained using the α-halo and α-mesyloxyketones, but with the advantages of simplicity in preparation and stability of the intermediates.
Ultrasound promoted hypervalent iodine reactions: (α-tosyloxylation of ketones with [hydroxy(tosyloxy)iodo]benzene
作者:Atilla Tuncay、John A. Dustman、George Fisher、Crystal I. Tuncay、Kenneth S. Suslick
DOI:10.1016/0040-4039(93)88006-5
日期:1992.12
the rates of α-tosyloxylation of ketones with [hydroxy(tosyloxy)iodo] benzene and thus provides a direct, quick, and mild method of tosyloxylation of ketones without the generation of time-consuming intermediates such as trimethylsilyl enol ether derivatives and α-hydroxy ketones. The present method also provides convenient access to the tosylates of alicyclic ketones such as cyclopentanone and cycloheptanone
A facile and regioselective synthesis of 1,4-disubstituted 1,2,3-triazoles using click chemistry
作者:Dalip Kumar、V. Buchi Reddy、Rajender S. Varma
DOI:10.1016/j.tetlet.2009.02.107
日期:2009.5
The reaction of α-tosyloxy ketones, sodium azide, and terminal alkynes in presence of copper(I) in aqueous polyethylene glycol afforded regioselectively 1,4-disubstituted 1,2,3-triazoles in good yield at ambient temperature. The one-pot exclusive formation of 1,4-disubstituted 1,2,3-triazoles involves in situ formation of α-azido ketones, followed by cycloaddition reaction with terminal alkyne. The
Oxy-Allyl Cation Catalysis: An Enantioselective Electrophilic Activation Mode
作者:Chun Liu、E. Zachary Oblak、Mark N. Vander Wal、Andrew K. Dilger、Danielle K. Almstead、David W. C. MacMillan
DOI:10.1021/jacs.5b13041
日期:2016.2.24
enantioselective conversion of racemic α-tosyloxy ketones to optically enriched α-indolic carbonyls has been accomplished using a new amino alcohol catalyst in the presence of electron-rich indole nucleophiles. Kineticstudies reveal that the rate-determining step in this S(N)1 pathway is the catalyst-mediated α-tosyloxy ketone deprotonation step to form an enantiodiscriminant oxy-allyl cation prior to