نتایج جستجو برای: cascade product

تعداد نتایج: 323343  

2011
Ya-Ping Xiao Xin-Yuan Liu Chi-Ming Che

The gold(I)/silver(I)-cocatalyzed cascade intermolecular N-Michael addition/intramolecular hydroalkylation reaction offers a simple and efficient method for the synthesis of pyrrolidine derivatives in moderate to excellent product yields and with moderate to good diastereoselectivities. The reaction conditions and the substrate scope of this reaction are examined, and a possible mechanism invol...

2014
Jillian E. Spangler Yajing Lian Sandeep N. Raikar Huw M. L. Davies

Treatment of (E)-1-(methoxymethylene)-1,2,3,4-tetrahydronaphthalene with styryl diazoacetates in the presence of catalytic amounts of the dirhodium complex Rh2(S-DOSP)4 provides a highly enantioenriched hexacyclic product with 10 new stereogenic centers. The transformation proceeds by a cascade sequence starting with a double cyclopropanation of a benzene ring, followed by a Cope rearrangement ...

Journal: :The Journal of organic chemistry 2014
Zhiyuan Chen Xuegong Jia Jiapian Huang Jianjun Yuan

A Pt(II)-catalyzed intramolecular chemo- and regioselective pentannulation/long-range 1,5-acyl migration reaction is described. This cascade cycloisomerization protocol produces a wide variety of benzofulvene diketones in good to excellent yields with exclusively the Z configuration of the exocyclic double bond of the final product. The (18)O isotope experiment together with (13)C NMR, HRMS, an...

Journal: :Chemical communications 2011
Pallavi Sharma Dougal J Ritson James Burnley John E Moses

A synthetic approach towards the structurally complex dimer, kingianin A is reported. The strategy involved a cascade of complexity generating reactions, inspired through biosynthetic speculation. A concise protecting group free synthesis of the proposed monomeric precursor pre-kingianin A has been achieved using a tandem Stille cross-coupling reaction and electrocyclisation process. However, p...

2017
Emma E. Blackham Kevin I. Booker‐Milburn

A short, 5-step total synthesis of (±)-3-demethoxyerythratidinone from a simple pyrrole derivative is described. Features include the formation of gram quantities of a key tricylic aziridine from a challenging photochemical cascade reaction through the use of flow photochemistry. The final step involved a highly unusual Heck cyclization whereby ligand control enabled efficient formation of the ...

Journal: :Organic & biomolecular chemistry 2003
Eric J Tisdale Irina Slobodov Emmanuel A Theodorakis

A concise synthesis of forbesione (1) and desoxymorellin (3) is presented. Central to the strategy is a biomimetic Claisen/Diels-Alder/Claisen reaction cascade that proceeds in a regioselective manner and produces the desired scaffold exclusively. The observed regioselectivity and product distribution of the Claisen/Diels-Alder/Claisen reaction are attributed to the electronic effects of the xa...

2016
Mohammad A. Alam Zakeyah Alsharif Hessa Alkhattabi Derika Jones Evan Delancey Adam Gottsponer Tianhong Yang

An efficient synthesis of novel 2,3-dihydro-4H-pyrido[1,2-a]pyrimidin-4-ones has been reported. Inexpensive and readily available substrates, environmentally benign reaction condition, and product formation up to quantitative yield are the key features of this methodology. Products are formed by the aza-Michael addition followed by intramolecular acyl substitution in a domino process. The polar...

Journal: :ITM web of conferences 2022

The research presents a method for assessing public acceptability of items based on their brand by analysing the facial expression consumer who intends to purchase product at supermarket. In such circumstances, face detection is crucial in evaluation. Emotions are conveyed through expressions. Sentimental analysis type natural language processing that may be used variety purposes. As result, se...

1999
Bradley A. Minch Paul E. Hasler Chris Diorio

We describe two systematic procedures for synthesizing mutlipleinput translinear element (MITE) networks that produce an output current that is equal to product of a number of input currents, each of which is raised to an arbitrary rational power. By using the first procedure, we obtain a MITE network, called a two-layer network, that is relatively insensitive to mismatch in the MITE weight val...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده علوم 1388

چکیده : حاصل ضرب خارجی جزئی یک گروه g در مقابل حاصل ضرب خارجی s(g) توسط : نرجس فریدونی پایان نامه حاضر بر اساس مقاله partial crossed product of a group g vs crossed product of s(g) نگارش r . exel and f . vieira نوشته شده است. در این پژوهش تعریف تازه ای برای حاصل ضرب خارجی جزئی بوسیله عمل های نیم گروه های معکوس در یک c^*-جبر، بدون استفاده از نمایش هموردا که ناندور سایبن در ]15...

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