Trimethylsilyl-2-propen-l-yl Acetate

Preparative Methods (i) from 3-trimethylsilyl-2-propyn-l-ol by reduction (sodium bis(2-methoxyethoxy) aluminum hydride (Red-Al), 70%) and acetylation (acetyl chloride, pyridine, 78%) (ii) from 3-trimethylsilyl-2-propyn-l-ol by reduction (P-2 raney nickel, H2, 86%) and acetylation (iii) from ally-loxytrimethylsilane by a metalation-rearrangement sequence (f-butyllithium, 90%) and acetylation (acetic anhydride, triethylamine, 76%).  

Other metals besides palladium are also effective. Reaction of the cationic allyltetracarbonyUron complex derived from (1) or (2) with silyl enol ethers, O-sUyl ketene acetals, or allylstan-nanes, followed by oxidative decomplexation, gives the vinyl-sUane products. The process was shown to occur with near complete retention of stereochemistry (cf. eqs 4 and 5).  

Nncleophilic Addition and Substitution Reactions. Allylsilane (3) has been shown to undergo conjugate addition to enones in the presence of tetra- -butylammonium fluoride (eq 6). The reaction demonstrates high regioselectivity, as no products arising from 1,2-addition to the enone or attack at the /-position of the allylsilane were isolated. Stereoselective C-glycosidation can be effected by reaction of allylsilane (3) with D-mannopyranoside derivatives in the presence of boron trifluoride etherate (eq 7). The a-C-glycoside arises from axial addition to the pyranoside oxonium ion. 

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TMS HC=CHCH20Ac E) HC=CHCH20Ac (Z) HC=CHCH20Ac ( +Z) 3-Trimethylsilyl-2-propen-l-yl Acetate ( ) 3-Trimethylsilyl-2-propen-l-yl Acetate (Z) 3-Trimethylsilyl-2-propen- 1-yl Acetate (E+Z mix) 86422-21-1 86422-22-2 80401-14-5 703... 

The discovery of palladium trimethylenemethane (TMM) cycloadditions by Trost and Chan over two decades ago constitutes one of the significant advancements in ring-construction methodology [1]. In their seminal work it was shown that in the presence of a palladium(O) catalyst, 2-[(trimethylsilyl)methyl]-2-propen-l-yl acetate (1) generates a TMM-Pd intermediate (2) that serves as the all-carbon 1,3-di-pole. It was further demonstrated that (2) could be efficiently trapped by an electron-deficient olefin to give a methylenecyclopentane via a [3-1-2] cycloaddition (Eq. 1). 

Several methods have been reported for the formation of cyclopentanes by 2 + 3 cycloadditions.908 One type involves reagents that produce intermediates 90 or 91.9"9 A synthetically useful example910 uses 2-[(trimethylsilyl)methyl]-2-propen-l-yl acetate (89) (which is com-... 

The presence of five-membered rings such as cyclopentanes, cyclopentenes, and dihydrofurans in a wide range of target molecules has led to a variety of methods for their preparation. One of the most successful of these is the use of trimethylenemethane [3-1-2] cycloaddition, catalysed by pal-ladium(O) complexes. The trimethylenemethane unit in these reactions is derived from 2-[(trimethylsilyl)methyl]-2-propen-l-yl acetate which is at the same time an allyl silane and an allylic acetate. This makes it a weak nucleophile and an electrophile in the presence of palladium(O). Formation of the palladium jt-allyl complex is followed by removal of the trimethylsilyl group by nucleophilic attack of the resulting acetate ion, thus producing a zwitterionic palladium complex that can undergo cycloaddition reactions. 

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