Reverse Regioselectivity in the Palladium(II) Thiourea Catalyzed Intermolecular Pauson-Khand Reaction
作者:Na Wu、Lujiang Deng、Lianzhu Liu、Qi Liu、Chuangchuang Li、Zhen Yang
DOI:10.1002/asia.201200783
日期:2013.1
Which way? Palladium thiourea catalyzed Pauson–Khand reaction of norbornene with substituted alkynoates to afford selectively either α‐carboxylated adducts or β‐carboxylated adducts with the reverse regioselectivity has been demonstrated for the first time. Control of the regioselectivity in this transformation is governed by the addition of LiCl. A mechanistic interpretation to account for this observed
The Asymmetric Aza-Claisen Rearrangement: Development of Widely Applicable Pentaphenylferrocenyl Palladacycle Catalysts
作者:Daniel F. Fischer、Assem Barakat、Zhuo-qun Xin、Matthias E. Weiss、René Peters
DOI:10.1002/chem.200900712
日期:2009.9.7
has a broader substrate tolerance than all previously known catalyst systems for asymmetric aza‐Claisen rearrangements. Our investigations also reveal that subtle changes can have a big impact on the activity. With the enhanced catalyst activity, the asymmetric aza‐Claisen rearrangement has a very broad scope: the methodology not only allows the formation of highly enantioenriched primary allylic amines
作者:Alan Armstrong、Paul A. Barsanti、Lyn H. Jones、Ghafoor Ahmed
DOI:10.1021/jo000700m
日期:2000.10.1
of (+)-zaragozic acid C is described. Key features of the synthesis are the use of a double Sharpless asymmetric dihydroxylation reaction of diene 6 to control stereochemistry at four contiguous stereocenters from C3 to C6; the introduction of the C1-side chain by reaction between the anion derived from the dithiane monosulfoxide 27 and the core aldehyde 12; a high yielding, acid-mediated simultaneous
Studies of neodolastanes — Synthesis of the tricyclic core of the trichoaurantianolides
作者:David R. Williams、Joseph R. Pinchman
DOI:10.1139/v2012-088
日期:2013.1
the synthesis of trichoaurantianolide C (5) are described. Stille cross-coupling reactions of (E)- and (Z)-β-stannyl-α,β-unsaturated esters with allylic acetate 32 provide for the stereocontrolled formation of nonconjugated 2,5-diene-1-ols. Studies of the asymmetric Sharpless epoxidation are utilized to establish diastereofacial selectivity for the preparation of a crucial C2 tertiary allylic alcohol
The synthesis of unnatural α-alkyl- and α-aryl-substituted serine derivatives
作者:Aleksandra Narczyk、Sebastian Stecko
DOI:10.1039/c9ob02472g
日期:——
The synthesis of α-aryl- and α-alkyl-substituted serine derivatives via [3,3]-sigmatropic rearrangement of allyl carbamates as a key step is reported. Allyl carbamates were obtained from the corresponding allyl alcohols. The former were prepared through three approaches. Aryl-substituted ones were synthesized via the Stille coupling reaction of aryl iodides with enantiomerically enriched vinyl stannanes