Ketone Super Silyl Enol Ethers in Sequential Reactions: Diastereoselective Generation of Tertiary Carbinols in One Pot
作者:Matthew B. Boxer、Matsujiro Akakura、Hisashi Yamamoto
DOI:10.1021/ja7102586
日期:2008.2.6
Ketone super silyl enolethers are shown to be excellent nucleophiles in the Mukaiyama aldol reaction as well as in sequential one-pot diastereoselective reactions. High yields and diastereoselectivities are obtained with a variety of silyl enolether/aldehyde/Grignard combinations. The utility of this reaction is exemplified in a one-pot 4-component reaction generating two secondary and one tertiary
Controlling stereochemistry in polyketide synthesis: 1,3- vs. 1,2-asymmetric induction in methyl ketone aldol additions to β-super siloxy aldehydes
作者:Patrick B. Brady、Brian J. Albert、Matsujiro Akakura、Hisashi Yamamoto
DOI:10.1039/c3sc51183a
日期:——
The aldol addition of methyl ketones to β-siloxy and α-methyl β-siloxy aldehydes is described. Careful control of mechanistically distinct aldol reactions leverages 1,2- and 1,3-asymmetric induction, selectively forming syn and anti aldol adducts with excellent diastereocontrol. Experimental and theoretical investigations have provided insight to the factors governing diastereoselectivity.
Rapid Total Syntheses Utilizing “Supersilyl” Chemistry
作者:Brian J. Albert、Yousuke Yamaoka、Hisashi Yamamoto
DOI:10.1002/anie.201007210
日期:2011.3.7
In short order: The shortest total syntheses of natural product EBC‐23 (see scheme, PMB=para‐methoxybenzyl, TMS=trimethylsilyl) and a polymethoxy‐1‐alkene to date have been accomplished in just ten total steps each from commercially available chemicals. The syntheses took advantage of highly diastereoselective supersilyl‐directed cascade polyaldol reactions.
Rapid and Stereochemically Flexible Synthesis of Polypropionates: Super-Silyl-Governed Aldol Cascades
作者:Patrick B. Brady、Hisashi Yamamoto
DOI:10.1002/anie.201108325
日期:2012.2.20
Polypropionates made EZ: The E/Z geometry of tris(trimethylsilyl)silyl super silyl enol ethers derived from propionaldehyde controls diastereoselectivity in the aldehyde crossed‐aldol reaction. These silyl enol ethers can participate in polyaldol cascade reactions, thus allowing the one‐pot synthesis of four different dipropionate stereotetrads (see scheme), and polyketides bearing up to five contiguous
Super Silyl Stereo-Directing Groups for Complete 1,5-Syn and -Anti Stereoselectivities in the Aldol Reactions of β-Siloxy Methyl Ketones with Aldehydes
作者:Yousuke Yamaoka、Hisashi Yamamoto
DOI:10.1021/ja101076q
日期:2010.4.21
-anti stereoinduction in the aldol reaction of beta-tris(trialkylsilyl)siloxy methylketones can be achieved with high diastereoselectivities. Tris(trialkylsilyl)silyl groups are easily prepared and play an important role in the selectivities of these reactions. Furthermore, all of the 1,3,5-triol stereoisomers can easily be prepared from beta-siloxy methylketones in no more than three steps.