Group alkoxy complexes

Reactions with acetals can serve to introduce (3-alkoxy groups into complex molecules, as in the following reaction.71... 

Alkoxy complexes of stoichiometry [Mo(OR)4] can be prepared from the reaction of [Mo(NMe2)4] with alcohols. With bulky groups (R = Bu , CH2Bu ) the complexes are... 

Pathways involving alkyl-acyl rearrangements are proposed to explain the carbonylation of a-bonded alkoxy complexes (17). The stereochemistry of the products indicates that the ester group replaces Pd with retention of configuration at the carbon to which Pd is o-bonded. In all these studies with unconjugated dienes the nature of carbonylation products to be expected is clearly influenced by the geometry of the intermediate Pd complexes. 

Reduction of TaCfr with Zn in the presence of aUcyne RC=CR and solvents (L) is believed to yield Ta chloro aUcyne complexes, which react with lithium aUcoxides tethered to alkenyl groups to give chemo- and stereoselective addition of terminal alkenyl groups. Alkoxy-directed insertion of C=C bonds into Ta-aUcyne complexes plays a critical role through the following mechanism. 

A number of facile procedures were developed for the synthesis of mono and bis cyclopentadienyl derivatives of titanium, e.g., the (tt-CsH )-trialkoxytitanium derivatives, (77-C5H5)-titanium trihalides (406, 407-409), (77-C5H5)-titanium internal complexes (409), triaroxytitanium cyclopentadienyls (410), compounds containing different groups (alkoxy, aryloxy. 

As we reported in our former works [3,4] alkoxide molecules underwent selective, stoichiometric reactions with surface hydroxyl groups. As a result of this reaction surface alkoxy complex was formed. 

The surface alkoxy complex was then decomposed by calcination of the catalyst in a stream of dry air at 623 K (see eq. 2). During the reaction, the evolution of stoichiometric amount of appropriate alkene was observed. Secondary hydroxyl groups appeared as a result of the reaction (2). Their presence created the possibility of anchoring the subsequent layer of the same or the other transition metal ions. 

Reductions. 3-Ketols and 3-alkoxy ketones are reduced to anti-1,3-diols and the monoethers, respectively. For the directed reduction, the alkoxy group must complex effectively with Sm, however, this is not observed with TBS and benzyl ethers. 

The link between the dioxymethylene function and P450 inhibition, the requirement for catalytic activation of the inhibitor, and the fact that the dioxymethylene group is oxidized implicate this function in the inhibitory events. An inhibitory role has been postulated for free radical, carbocation, and carbanion intermediates, but formation of the carbene from the bridge-hydroxylated metabolite or from its radical precursor is most consistent with the results (Figure 7.12). Substituents other than an alkoxy group on the dioxymethylene group suppress complex formation The retention of... 

Another interesting family of square-planar metallomesogens is that constituted by complexes of enaminoketones. Several copper complexes of type (233a) and (233b), with various n and w, have been synthesized, and when R is an alkoxy (OC H2 +i), alkyl (C H2/j+i), or alkanoate (C02C H2j,+i) group, the complexes are not liquid crystals, or exceptionally showed a monotropic SniA phase. ... 

S57mmetrical alltynes provide access to carbyne complexes 42 upon reaction with symmetrical triply bonded tungsten alkoxy, aryloxy, and mixed allg l-alkoxy complexes (Scheme This reaction occurs readily when R is a simple allg l group but also... 

A third and very practical alternative is the resolution of racemic acyliron complexes by crystallization with (5)-(+)- or (/ )-(-)-camphersulfonic acid via the diastereomeric hydroxycarbene salts and subsequent neutralization. Conversion of the enantiomerically pure acetyliron complexes to a-alkoxy complexes and subsequent trimethylsilyl triflate-mediated removal of the methoxy group provides enantiomerically pure (ethylidene)iron complexes.Methylation of alkynoyliron complexes with Meerwein s salt has been reported to give cationic methoxy-substituted alkynylcarbenes, which can be transformed into the corresponding (aminocarbene)iron complexes upon reaction with primary amines. " Meerwein s salt can also be used to form cationic... 

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