Highly Diastereoselective Hydrostannylation of Allyl and Homoallyl Alcohols with Dibutyl(trifluoromethanesulfoxy)stannane
摘要:
Dibutyl(trifluoromethanesulfoxy)stannane (Bu2Sn(OTf)H, 1a) was found to be very valuable for highly diastereoselective homolytic hydrostannylation of allyl and homoallyl alcohols. alpha,beta-Disubstituted allyl alcohols and alpha,gamma-disubstituted homoallyl alcohols were converted into gamma- and delta-stannylated alcohols with high 1,2-syn and 1,3-syn diastereoselectivity, respectively. The origin of the stereochemical outcomes can be rationalized by conformational fixation of the intermediary beta-stannylalkyl radical by coordination of the hydroxy group to the Lewis acidic tin center.
Radical condensation between benzylic alcohols and acetamides to form 3-arylpropanamides
作者:Kobra Azizi、Robert Madsen
DOI:10.1039/d0sc02948c
日期:——
A new radical condensation reaction is developed where benzylic alcohols and acetamides are coupled to generate 3-arylpropanamides with water as the only byproduct. The transformation is performed with potassiumtert-butoxide as the only additive and gives rise to a variety of 3-arylpropanamides in good yields. The mechanism has been investigated experimentally with labelled substrates, trapping experiments
Alkenyl (or aryl) iodide (or bromide) is readily reduced with CrCl2 is N,N-dimethylformamide at 25°C to gice the corresponding organochromium species which adds selectively to an aldehyde moiety without affecting the coexisting ketone or cyano group of the substrate.
Cp*Ru(PN) Complex-Catalyzed Isomerization of Allylic Alcohols and Its Application to the Asymmetric Synthesis of Muscone
作者:Masato Ito、Sachiko Kitahara、Takao Ikariya
DOI:10.1021/ja050770g
日期:2005.5.1
Highly efficient isomerization of allylicalcohols into saturated carbonyls is accomplished using the catalyst system of Cp*RuCl[Ph2P(CH2)2NH2-kappa2-P,N]-KOt-Bu (Cp* = eta5-C5(CH3)5) under mild conditions. Mechanistic consideration based on isotope-labeling experiments indicated the present reaction is applicable to the asymmetricisomerization of racemic sec-allylic alcohols with a prochiral olefin
inclination of other 17-electron metal carbonyl complexes to undergo associative ligand displacement reactions, it seems ironic that the incorporation of a pentadienyl ligand, which would be expected to promote associative attack via $ 73 coordination changes, should lead instead to a series of compounds for which much lower rates of substitution are observed and for which the substitutions also take place
Arylation and Vinylation of Alkenes Based on Unusual Sequential Semipinacol Rearrangement/Grob Fragmentation of Allylic Alcohols
作者:Dao-Yi Yuan、Yong-Qiang Tu、Chun-An Fan
DOI:10.1021/jo801434b
日期:2008.10.3
Alkenes can be stereoselectively arylated and vinylated without transition-metal catalyst under mild conditions through an interesting NBS-promoted semipinacol rearrangement and a subsequent unusual NaOH-mediated Grob fragmentation.