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Alkyne derivatives

Syntheses using alkyne-derived alkenyl- and alkynylaluminium compounds G. Zweifel and J. A. Miller, Organic Reactions 32, 375 (1984). [Pg.164]

Even though the reaction proceeded smoothly at the C-3 position of the pyrazinone scaffold providing the alkyne derivative in good yields, no reaction was observed at the C-5 position under similar conditions. [Pg.279]

Stable zirconate complexes of type 31 have also been described by the [3 + 2] cycloaddition of a-phosphino zirconaindene with alkyne derivatives, and the method has been extended to the synthesis of zirconium complexes from various heterocumulenes X=C=Y (X,Y=0,S,CyN) (Scheme 15) [69,70]. [Pg.53]

The diamagnetic ylide complexes 34 have been obtained from the reaction of electron-deficient complexes [MoH(SR)3(PMePh2)] and alkynes (HC=CTol for the scheme), via the formal insertion of the latter into the Mo-P bond. The structural data show that 34 corresponds to two different resonance-stabilized ylides forms 34a (a-vinyl form) and 34b (carbene ylide form) (Scheme 17) [73]. Concerning the group 7 recent examples of cis ylide rhenium complexes 36 cis-Me-Re-Me) have been reported from the reaction of the corresponding trans cationic alkyne derivatives 35 with PR" via a nucleophilic attack of this phosphine at the alkyne carbon. [Pg.54]

A different synthetic access to a 1 -metallacyclopropene, which can be a versatile organometallic synthon, is displayed in Scheme 33. The mono-alkyne derivatives of W(IV)-calix[4]arene are easily accessible through the thermal displacement of cyclohexene from 32 using the appropriate acetylenes. The reaction led to complexes 34 and 172-174. The proposed 3-metallacyclopropene has been confirmed from the spectroscopic and the X-ray data. The H NMR data reveal a cone conformation of the calixarene with a four-fold symmetry, for which the... [Pg.217]

A first example of a combination of a Rh-catalyzed allylic substitution and a Pau-son-Khand annulation reaction has also been developed by the same group [222]. Thus, [RhCl(CO)dppp]2 is able to catalyze both transformations at different reaction temperatures. Treatment of the allylic carbonate 6-106 with the alkyne derivative 6-107 led to a diastereomeric mixture of 6-108 and 6-109 in 63-84% yield, with 6-108 as the main product (Scheme 6/2.23). [Pg.438]

Figure 17.13 Expressed proteins containing a thioester intein tag can be specifically modified using a cysteine-alkyne derivative by transthioesterification followed by an internal S - N shift. Figure 17.13 Expressed proteins containing a thioester intein tag can be specifically modified using a cysteine-alkyne derivative by transthioesterification followed by an internal S - N shift.
Recently, Oshima has reported a cobalt-catalyzed allylzincation of internal alkyne derivatives (Scheme 10). Optimization of the reaction leads to utilization of cobalt(ll) chloride in THF at room temperature. No traces of regio- and stereoisomers are obtained. The resulting alkenylzinc species 34 can be trapped with a large number of electrophiles in order to generate stereoselectively the tri- and tetrasubstituted alkenes 35-37. [Pg.304]

Acylzirconocene chloride derivatives are easily accessible in a one-pot procedure through the hydrozirconation of alkene or alkyne derivatives with zirconocene chloride hydride (Schwartz reagent) [Cp2Zr(H)Cl, Cp = cyclopentadienyl] and subsequent insertion of carbon monoxide (CO) into the alkyl— or alkenyl—zirconium bond under atmospheric pressure (Scheme 5.1) [2],... [Pg.149]

Having pyrazinylacetylenes in hand, one could convert the alkynyne functionality into the corresponding ketone via hydration [33], Thus, the coupling of iodide 36 and acetylene 37 produced pyrazinylalkyne 38. Subsequent exposure of 38 to aqueous sodium sulfide and aqueous hydrochloric acid in methanol led to ketone 39. Such a maneuver provides additional opportunities for further manipulation of the alkynes derived from the Sonogashira coupling reactions. [Pg.360]

As described in this chapter, vinylidene complexes of Group 6 metals have been utilized for the preparation of various synthetically useful compounds through electrophilic activation or electrocyclization of terminal alkyne derivatives. These intermediates are quite easily generated from terminal alkynes and M(CO)6, mostly by photo-irradiation and will have abundant possibilities for the catalytic activation of terminal alkynes. Furthermore, it should be emphasized that one of the most notable characteristic features of the vinylidene complexes of Group 6 metals is their dynamic equilibrium with the it-alkyne complex. Control of such an equilibrium would bring about new possibilities for unique metal catalysis in synthetic reactions. [Pg.187]

Enantiomerically-pure sulfoxides are readily available. Ilan Marek of Technion-Israel Institute of Technology reports (1. Am. Chem. Soc. 125 11776, 2003) that alkyne-derived sulfoxides such as 8 can be used to direct the addition of an allylic organometallic, prepared in situ, to an aldehyde 9. Both the secondary alcohol, from the aldehyde, and the adjacent quaternary center of 10 are formed with >99% stereocontrol. [Pg.141]

The polymerization of substituted alkynes is postulated to proceed either by the metathesis mechanism or by an insertion mechanism (18). Numerous alkyne derivates have been shown to polymerize in the presence of group V, VI, and VIII transition metal catalysts. [Pg.26]

Oxotetrahydrothiophenes form enamines (78S368). Such 3-amino-4,5-dihydrothio-phenes undergo [2 + 2] cycloaddition with alkyne derivatives (Scheme 210) (77AHC(21)253>. [Pg.848]

Scheme 5.70. Carbanion-carbene tautomery of vinylic or alkyne-derived carbanions substituted with electron-withdrawing groups. Scheme 5.70. Carbanion-carbene tautomery of vinylic or alkyne-derived carbanions substituted with electron-withdrawing groups.

See other pages where Alkyne derivatives is mentioned: [Pg.310]    [Pg.87]    [Pg.26]    [Pg.26]    [Pg.308]    [Pg.212]    [Pg.386]    [Pg.308]    [Pg.456]    [Pg.111]    [Pg.668]    [Pg.323]    [Pg.144]    [Pg.79]    [Pg.352]    [Pg.264]    [Pg.72]    [Pg.146]    [Pg.51]    [Pg.357]    [Pg.768]    [Pg.895]    [Pg.267]    [Pg.267]    [Pg.309]    [Pg.434]    [Pg.378]    [Pg.349]    [Pg.160]   
See also in sourсe #XX -- [ Pg.1237 ]

See also in sourсe #XX -- [ Pg.1237 ]




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Acetylene derivs alkynes

Acetylenes alkyne derivatives

Acylpalladium derivatives alkynes

Alkane derivatives alkyne hydrogenation

Alkyne Cinchona Alkaloids, Their Derivatives, and Basic Transformations

Alkyne derivatives Sonogashira synthesis

Alkyne derivatives Stille reactions

Alkyne derivatives aldehyde trapping

Alkyne derivatives alkoxycarbonylation

Alkyne derivatives alkynylsilane

Alkyne derivatives carbonylation

Alkyne derivatives carbopalladation

Alkyne derivatives cascade carbopalladation

Alkyne derivatives copper-catalyzed halides, terminal

Alkyne derivatives coupling

Alkyne derivatives coupling conditions, terminal alkynes

Alkyne derivatives formate anions

Alkyne derivatives haloalkynes

Alkyne derivatives heterocyclic synthesis

Alkyne derivatives homocoupling reactions

Alkyne derivatives hydrocarboxylation

Alkyne derivatives hydroformylation

Alkyne derivatives insertion

Alkyne derivatives intermolecular carbopalladation

Alkyne derivatives intermolecular reactions

Alkyne derivatives intramolecular carbopalladation

Alkyne derivatives intramolecular reactions

Alkyne derivatives ketone trapping

Alkyne derivatives lactamization

Alkyne derivatives leaving groups

Alkyne derivatives mechanisms

Alkyne derivatives metal-catalyzed reactions

Alkyne derivatives metallated systems

Alkyne derivatives natural products synthesis

Alkyne derivatives organometals

Alkyne derivatives polymers

Alkyne derivatives reaction scope

Alkyne derivatives reactivity

Alkyne derivatives reagents

Alkyne derivatives reductive elimination

Alkyne derivatives regiochemistry

Alkyne derivatives stereochemistry

Alkyne derivatives synthesis-based cross-coupling

Alkyne derivatives systems

Alkyne derivatives terminal acetylenes

Alkyne derivatives trapping

Alkyne-derived complexes

Alkynes : derivatives structure

Alkynes acetylides, derived

Alkynes addition of sulphur-derived

Alkynes and their derivatives

Alkynes benzene derivatives

Alkynes copper derivatives

Alkynes enyne derivatives

Alkynes metal derivatives

Alkynes organometallic derivatives

Alkynes thiocarbonyl derivatives

Alkynes, cyclization derivatives

Alkynes, reaction with pyrrole derivatives

Amides, from acid derivatives alkynes

Carboxylic acids alkyne derivatives

Cluster complexes alkyne derivatives

Compounds Derived from Alkynes and Carbonyl Complexes of Cobalt

Enynes alkyne derivatives

Formate derivatives alkyne carbopalladation

Isomerization alkene/alkyne derivatives

Ketones alkyne derivatives

Markovnikov additions alkyne derivatives

Oxidation reactions alkyne derivatives

Phenols reactions, alkyne derivatives with

Potassium alkyne derivatives

RXN4 Cross-Coupling of Terminal Alkynes with RX Derivatives

Ring systems alkyne derivatives

Sodium alkyne derivatives

Transfer hydrogenation alkyne derivatives

Transition-metal derivatives alkyne insertion into

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