2- Trimethylsilylmethyl-1,3-butadiene

Trimethylsilyl)methylallyl iodide, 579 2-Trimethylsilylmethyl-1,3-butadiene, 580 Trimethylsilylmethyllithium, 581 Trimethylsilylmethylmagnesium chloride, 58,... 

Isoprenylation. Like other allylic silanes, 2-trimethylsilylmethyl-1,3-butadiene reacts with various electrophilic species such as acetals, acid chlorides, and carbonyl compounds with the aid of a Lewis acid to give the corresponding isoprenylated compounds (eqs 3-6). 

The direct reaction of 2-trimethylsilylmethyl-1,3-butadiene with isovaleraldehyde gives ( )-ipsenol (2-methyl-6-methylene-7-octen-4-ol) in rather low yield (30%) (eq 5). However, ipsenol is obtained in 62% overall yield by the reaction of 2-trimethylsilylmethyl-1,3-butadiene with isovaleryl chloride, followed by reduction with diisobutylaluminum hydride (eq 7). Similarly, ( )-ipsdienol (2-methyl-6-methylene-2,7-octadien-4-ol) is obtained by reduction of myrcenone, prepared by the reaction of 2-trimethylsilylmethyl-1,3-butadiene with 3,3-dimethylacryloyl chloride, in 75% overall yield (eq 8). 

The methyl ether of ipsenol can be prepared by the reaction of 2-trimethylsilylmethyl-1,3-butadiene and isovaleraldehyde... 

Trimethylsilylmethyl-1,3-butadiene undergoes highly re-gioselective aluminum chloride-catalyzed Diels-Alder reactions with dienophiles such as acrolein and methyl vinyl ketone in which the "para isomers are obtained almost exclusively (eqs 13 and 14). The adducts are converted readily to a variety of naturally occurring mono- and sesquiterpenes (eq 15). ... 

Formation of w-Allylic Complex Followed by Acyldemet-alation. 2-Trimethylsilylmethyl-1,3-butadiene forms a titanium(III) complex by the reaction with dichlorobis-(cyclopentadienyl)titanium and n-PrMgBr. The complex reacts with carboxylic acid chlorides RCOCl (R = alkyl, alkenyl) to give, y-unsaturated ketones (eq 16). ... 

The regioselectivity of nucleophilic additions to the Co(CO)3BF4 complex has also been examined.i Ziegler-Natta polymerization of 2-trimethylsilylmethyl-1,3-butadiene catalyzed by triethylaluminum and titanium(IV) chloride gives predominantly cis-1,4-polymer. However, anionic polymerization yields a polymer whose microstmcture is conqtosed of cis-1,4-, trans-1,4-, and 3,4-units.i ... 

ISOPREPENYLATION Aluminum chloride. Aluminum chloride-Potassium pheno-xide. Carbon disulfide-Methyl iodide. 2-Trimethylsilylmethyl-l, 3-butadiene. 2-Trimethylsilylmethylenecyclobutane. 

Table 3 Diels-Alder Reactions of Isoprene, 2-Trimethylsilylmethyl- and 2-Ttimethylstannylmethyl-1,3-butadienes with Conjugated Enoyl Compounds (Scheme 43)...

The bis(trimethylsilylmethyl)platinum complex 126 with 1,4-diaza-l,3-butadiene undergoes protonolysis by 2,2,2-... 

Diels-Alder Reactions. 2-Trimethylsilylmethyl-1,2-butadiene and 2-trimethylstannylmethyl-1,3-butadiene undergo facile cycloaddition with dienophiles (eq 11). The reactions of 2-trimethylsilylmethyl- and 2-trimethylstannylmethyl-1,3-butadiene with unsymmetrical dienophiles give the so-called para product predominantly, and the selectivity is much higher in the reactions with 2-trimethylsilylmethyl- and 2-trimethylstarmylmethyl-1,3-butadiene compared to reactions with isoprene. The paralmeta ratios in the reactions with methyl acrylate (eq 12) are 70/30 (X = H), 84/16 (X = SiMej), and 91/9 (X = SnMes)."... 

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