Dimethylketene methyl trimethylsilyl acetal

A nonionic way of polymerizing MVK is the group transfer polymerization (GTP) with dimethylketene methyl trimethylsilyl acetal as intiator and the MegSiFa anion delivered from tris(dimethylamino)sulfonium difluorotrimethylsilicate (TASF2SiMe3)... 

Alternate Name dimethylketene methyl trimethylsilyl acetal. Physical Data bp 35 °Cyi5 mmHg d 0.858 g cm . ... 

A, A-Dialkylacrylamides also undergo group-transfer polymerization to provide polymers in good to quantitative yields. Sogah and Webster have reported that the polymerization of DMA can be initiated with dimethylketene methyl trimethylsilyl acetal in THF (Sogah et al, 1987). Poly(DMA) was quantitatively obtained, while the number-average molecular weight was apparently lower than the theoretical one and the MWD was fairly broad = 1.62). On... 

Functionalized initiators. Their use leads to terminal functionalized polymers. Thus, with phosphorus-containing ketene silyl acetals, trimethylsilyl methyl sulfide, trimethylsilyl cyanide, dimethylketene-bis(trimethylsilyl)acetal, or dimethylketene-2-(trimethylsiloxy) ethyltrimethyl silyl acetal, terminal phosphoric acid groups, thiomethyl groups, and cyanide, hydroxy, or carboxyl groups are readily introduced [234]. Furthermore, the styrene end group can also be achieved [247]. 

Adapted from Sasidharan and Kumar (257). Reaction conditions catalyst, 150 mg methyl trimethylsilyl dimethylketene acetal (silyl enol ether), 10 mmol a,(3-unsaturated carbonyl compounds, 10 mmol dry THF, 10 mmol reaction temperature, 333 K reaction time, 14 h. Structures of a, p-unsaturated carbonyl compounds (2a-2g) and products (3a-3g) are shown in Scheme 24. 

Introducing the Tau residue into a peptide according to the first approach demands protection of the amino group, usually in the form of a Z-derivative and turning the sulfonic acid into sulfonyl chloride. Synthesis of (j-su Ifonamidopeptides via an iterative process, both in solution and in the solid phase, has been described.11201 Chiral methylene sulfinamide peptides can be synthesized both in solution and in the solid phase using the sulfonyl chlorides derived from enantiomerically pure 2-substituted taurines under mild coupling conditions (DMAP catalysis and excess methyl trimethylsilyl dimethylketene acetal as a proton trap).11261... 

To the carlxMiyl compound (1 37.2 mmol) in a dry flask under nitrogen atmosphere were added anhydrous THF (37.2 mL), methyl trimethylsilyl dimethylketene acetal/l-methoxy-l-t rt-butyldimethylsilylethene (2 55.7 nunol) and NHC (I 0.37 mmol). The mixture was stirred at room temperature (23 C) for 20 h. The volatiles were then removed via eparoation, and the residue was distilled under vacuum to afford silyl enol ether 3. Each of the products was characterized based on spectral studies. 

However, mention should be made of the use of a trimethylsilyl methyl acetal of dimethylketene as an initiator for addition polymerization " and characterization or detection of compounds with Si=Si or Si=C bonds or containing divalent silicon or interchanges between these species. The chemistry of reactive intermediates in organosilicon chemistry has been reviewed by Barton."... 

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