نتایج جستجو برای: mukaiyama

تعداد نتایج: 161  

Journal: :Natural product reports 2014
Markus Kalesse Martin Cordes Gerrit Symkenberg Hai-Hua Lu

The vinylogous Mukaiyama aldol reaction (VMAR) allows efficient access to larger segments for complex natural product synthesis, primarily polyketides, through the construction of vicinal hydroxyl and methyl groups as well as di and tri-substituted double bonds in one single operation. In this review, we will highlight stereoselective protocols that have been used in natural product synthesis a...

Journal: :Journal of the American Chemical Society 2010
Yujiang Mei Prabani Dissanayake Matthew J Allen

The development of aqueous methods for generating enantiopure β-hydroxy carbonyl compounds is an important goal because these subunits compose many bioactive compounds and the ability to synthesize these groups in water has environmental and cost benefits. In this communication, we report a new class of ligands for aqueous, lanthanide-catalyzed, asymmetric Mukaiyama aldol reactions for the synt...

Journal: :Organic & biomolecular chemistry 2016
Yunjeong Park Mikyung Sim Tong-Shin Chang Jae-Sang Ryu

We have developed a straightforward and auxiliary-free synthetic route towards tBu-tubuphenylalanine (tBu-Tup) and tBu-epi-tubuphenylalanine (tBu-epi-Tup), which are the key components of tubulysins and their analogs. A Lewis acid-mediated diastereoselective Mukaiyama aldol reaction using silyl ketene acetal and N-Boc-L-phenylalaninal provided γ-amino-β-hydroxyl-α-methyl esters, which were deox...

2016
Luisruben P. Martinez Shigenobu Umemiya Sarah E. Wengryniuk Phil S. Baran

The structurally intriguing terpenes pallambins C and D have been assembled in only 11 steps from a cheap commodity chemical: furfuryl alcohol. This synthesis, which features a redox-economic approach free of protecting-group manipulations, assembles all four-ring systems via a sequential cyclization strategy. Of these four-ring constructing operations, two are classical (Robinson annulation an...

Journal: :Organic & biomolecular chemistry 2010
Vincenzo Zambrano Gloria Rassu Annamaria Roggio Luigi Pinna Franca Zanardi Claudio Curti Giovanni Casiraghi Lucia Battistini

An efficient, stereocontrolled synthesis of (6S,7S,8S,8aR)-6,7,8-trihydroxyindolizidine (alias 1-deoxy-7,8-di-epi-castanospermine) (14) has been developed, which exploits an asymmetric vinylogous Mukaiyama aldol reaction (VMAR) between N-(tert-butoxycarbonyl)-2-(tert-butyldimethylsilyloxy)pyrrole (1) and 2,3-O-isopropylidene-D-glyceraldehyde (2) to construct the initial pyrrolidine building blo...

2014
Manuel Peifer Raphaëlle Berger Valerie W. Shurtleff Jay C. Conrad David W. C. MacMillan

An efficient route towards biologically relevant pentose derivatives is described. The de novo synthetic strategy features an enantioselective α-oxidation reaction enabled by a chiral amine in conjunction with copper(II) catalysis. A subsequent Mukaiyama aldol coupling allows for the incorporation of a wide array of modular two-carbon fragments. Lactone intermediates accessed via this route pro...

Journal: :Journal of the American Chemical Society 2008
David A Evans Lisbet Kvaernø Travis B Dunn André Beauchemin Brian Raymer Jason A Mulder Edward J Olhava Martin Juhl Katsuji Kagechika David A Favor

The synthesis of the marine neurotoxin azaspiracid-1 has been accomplished. The individual fragments were synthesized by catalytic enantioselective processes: A hetero-Diels-Alder reaction to afford the E- and HI-ring fragments, a carbonyl-ene reaction to furnish the CD-ring fragment, and a Mukaiyama aldol reaction to deliver the FG-ring fragment. The subsequent fragment couplings were accompli...

Journal: :Angewandte Chemie 2011
Lars Ratjen Pilar García-García Frank Lay Michael Edmund Beck Benjamin List

The term vinylogy, which describes a unique property of p systems where the electron density and reactivity is amplified along conjugated bonds, was proposed 75 years ago by Fuson. The principle becomes particularly relevant in the context of the aldol reaction: While metal dienolates often furnish mixtures of aand g-addition products, the corresponding dienolsilanes react with high selectivity...

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