scholarly journals Copper-catalyzed synthesis of allenylboronic acids. Access to sterically encumbered homopropargylic alcohols and amines by propargylboration

2018 ◽  
Vol 9 (13) ◽  
pp. 3305-3312 ◽  
Author(s):  
Jian Zhao ◽  
Sybrand J. T. Jonker ◽  
Denise N. Meyer ◽  
Göran Schulz ◽  
C. Duc Tran ◽  
...  
Keyword(s):  
Homopropargylic Alcohols

Synthesis and application of allenylboronic acids is presented. The successful synthetic applications are based on the possibility of the versatile transformations of the unprotected B(OH)2 group in situ under the propargylboration conditions.

In situ generation of 2,3-allenolates in the coupling of secondary homopropargylic alcohols and aldehydes

2006 ◽  
Vol 47 (3) ◽  
pp. 283-286 ◽  
Author(s):  
Pedro O. Miranda ◽  
Miguel A. Ramírez ◽  
Juan I. Padrón ◽  
Víctor S. Martín
Keyword(s):  
Homopropargylic Alcohols ◽  
In Situ Generation

scholarly journals NbCl5-Mg Reagent System in Regio- and Stereoselective Synthesis of (2Z)-Alkenylamines and (3Z)-Alkenylols from Substituted 2-Alkynylamines and 3-Alkynylols

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3722
Author(s):  
Rita N. Kadikova ◽  
Azat M. Gabdullin ◽  
Oleg S. Mozgovoj ◽  
Ilfir R. Ramazanov ◽  
Usein M. Dzhemilev
Keyword(s):  
Double Bond ◽  
Stereoselective Synthesis ◽  
Efficient Tool ◽  
Magnesium Metal ◽  
Methanesulfonyl Chloride ◽  
Homoallylic Alcohols ◽  
Homopropargylic Alcohols ◽  
Stereoselective Method ◽  
High Yields

The reduction of N,N-disubstituted 2-alkynylamines and substituted 3-alkynylols using the NbCl5–Mg reagent system affords the corresponding dideuterated (2Z)-alkenylamine and (3Z)-alkenylol derivatives in high yields in a regio- and stereoselective manner through the deuterolysis (or hydrolysis). The reaction of substituted propargylamines and homopropargylic alcohols with the in situ generated low-valent niobium complex (based on the reaction of NbCl5 with magnesium metal) is an efficient tool for the synthesis of allylamines and homoallylic alcohols bearing a 1,2-disubstituted double bond. It was found that the well-known approach for the reduction of alkynes based on the use of the TaCl5-Mg reagent system does not work for 2-alkynylamines and 3-alkynylols. Thus, this article reveals a difference in the behavior of two reagent systems—NbCl5-Mg and TaCl5-Mg, in relation to oxygen- and nitrogen-containing alkynes. A regio- and stereoselective method was developed for the synthesis of nitrogen-containing E-β-chlorovinyl sulfides based on the reaction of 2-alkynylamines with three equivalents of methanesulfonyl chloride in the presence of stoichiometric amounts of niobium(V) chloride and magnesium metal in toluene.

In situ Generation of 2,3-Allenolates in the Coupling of Secondary Homopropargylic Alcohols and Aldehydes.

ChemInform ◽  
2006 ◽  
Vol 37 (17) ◽  
Author(s):  
Pedro O. Miranda ◽  
Miguel A. Ramirez ◽  
Juan I. Padron ◽  
Victor S. Martin
Keyword(s):  
Homopropargylic Alcohols ◽  
In Situ Generation

Rendez vous with Saturn's rings

1984 ◽  
Vol 75 ◽  
pp. 743-759 ◽  
Author(s):  
Kerry T. Nock
Keyword(s):  
Solar Energy ◽  
Electric Propulsion ◽  
Power Source ◽  
Propulsion System ◽  
Low Thrust ◽  
Ring Plane ◽  
The Earth ◽  
Total Impulse ◽  
Saturn's Rings

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.

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