Alkylation tetramer

Tertiary amines also depolymerize lithium alkyl tetramers and hexamers and can be used to trigger reactions with alkyl halides (Lepley, 1968). However, when triethylamine is used to initiate the butyl... 

A novel Wittig-hke route to 5-substituted 4-aIkoxy-3-pyrrolin-2-ones (alkyl tetramates) utilizing a resin-bound cumulated yhde has been reported by the Schobert group (Scheme 28 2004OBC3524, 2005T2301). 

Huang P-Q, Wu T-J, Ruan Y-P. A flexible approach to (S)-5-alkyl tetramic acid derivatives application to the asymmetric synthesis of (-l-)-preussin and protected (3S,4S)-AHPPA. Org. Lett. 2003 5(23) 4341 344. 

Fig. 1. Stmctures of alkyllithium tetramers and hexamers (a) tetrahedron of lithium alkyl groups (b) arrangement of alkyl groups around octahedron of...

Nonene, or propylene tetramer, is used to alkylate phenol, which is subsequently ethoxylated to produce nonylphenol ethoxylate, an efficient, rehable industrial surfactant. 

Detergent All late. In the 1940s, sodium dodecylben2ene sulfonate [25155-30-0] (DDES) produced by the alkylation of ben2ene with propylene tetramer followed by sulfonation with oleum [8014-95-7] (H2SO4 mixture with sulfur trioxide) or sulfur trioxide and then neutrali2ation... 

Of interest is the relative composition of the LABs, particularly the different amount of 2-phenyl isomer and of nonlinear alkylates, given in Table 8. Branched alkylbenzene (BAB) formed by the AlCl3-catalyzed reaction between propylene, condensed to its tetramer, and benzene are less biodegradable and are termed biologically hard. LABs have to a large extent replaced BABs in the domestic markets because of their improved biodegradability. 

These facts are perfectly matched with our above-mentioned desired requirements. In addition, alkyl zinc is known to be less basic and deprotonation of ketone-aniline 36 by zinc reagent is highly unlikely. However, one of the issues for this reaction was the requirement for two alkyl groups on the zinc metal since the product ends up as tetramer 61, where the zinc atom still has one alkyl group, recalling that our cyclopropylacetylene (37) is not easy to obtain. 

All of the soluble polymers (1 and 3-6) give high resolution NMR spectra (1H, 13C, and 31P) that are completely consistent with their proposed structures. As observed for other types of poly(phosphazenes), the 31P chemical shifts of these alkyl/aryl substituted polymers are consistently ca. 15-30 ppm upfield from those of the analogous cyclic trimers and tetramers. Some important structural information is provided by 13C NMR spectroscopy, particularly for the phenyl/alkyl derivatives 3 and 4. These polymers are rare examples of phos-phazenes that contain two different substituents at each phosphorus atom in the chain. Thus, they have the possibility of being stereoregular. The fact that the structures are completely atactic, however, is confirmed by the observation of three doublets in the P-Me region of the 13C NMR spectrum (ca. 22 ppm) in a 1 2 1 intensity ratio. 

Transformations through 1,2-addition to a formal PN double bond within the delocalized rc-electron system have been reported for the benzo-l,3,2-diazaphospholes 5 which are readily produced by thermally induced depolymerization of tetramers 6 [13] (Scheme 2). The monomers react further with mono- or difunctional acyl chlorides to give 2-chloro-l,3,2-diazaphospholenes with exocyclic amide functionalities at one nitrogen atom [34], Similar reactions of 6 with methyl triflate were found to proceed even at room temperature to give l-methyl-3-alkyl-benzo-l,3,2-diazaphospholenium triflates [35, 36], The reported butyl halide elimination from NHP precursor 13 to generate 1,3,2-diazaphosphole 14 upon heating to 250°C and the subsequent amine addition to furnish 15 (Scheme 5) illustrates another example of the reversibility of addition-elimination reactions [37],... 

The zinc atom has almost ideal tetrahedral coordination geometry, with bond angles ranging from 115.37(10)° to 123.60(9)°. The zinc-carbon bond (1.964(3) A) has a similar length as in the neutral [MeZn(OBut)]4 tetramer,106 in which zinc is also tetrahedrally surrounded by one alkyl group and three oxygen atoms. 

A great deal of effort has been directed to determining the structures of lithium alkyls. It has been determined that in hydrocarbon solutions the dominant species is a hexamer when the alkyl groups are small. In the solid phase, the structure is body-centered cubic with the (LiCH3)4 units at each lattice site. Each unit is a tetramer in which the four lithium atoms reside at the comers of a tetrahedron and the methyl groups are located above the centers of the triangular faces. The carbon atoms of... 

Other organometallic compounds of aluminum include the alkyl hydrides, R2A1H. Molecular association of these compounds leads to cyclic tetramers. When the dimeric and trimeric compounds are dissolved in a basic aprotic solvent, the aggregates separate as a result of formation of bonds between A1 and the unshared pair of electrons on the solvent molecule. Toward Lewis bases such as trimeth-ylamine, aluminum alkyls are strong Lewis acids (as are aluminum halides). 

Novel highly functionalized dipeptide isosters were synthesized via diastereoselective alkyl-arylation protocol of a glucose-derived (R)-tert-butanesulfinylimine. One of these novel sugar amino acid derivatives, a D-Ala-Ser/Thr isostere, was applied in a peptide synthesis protocol to afford a cyclic tetramer (Fig. 53).69... 

Cyclic trimers and tetramers have been reported by Fritz and Raabe128. These were presumed to arise from intermediates formed in the dissociation of tetramethyl silicon by C-H bond rupture. This seems unlikely, but the same precursors could be formed by hydrogen abstraction from the parent compound. The available evidence indicates that the decomposition does not involve long chains, but free radical attack on the alkyl by the reactions... 

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