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Terminal alkynes intramolecular silylformylation

Intramolecular cyclization is particularly effective to terminal alkynes containing three or four methylene units between acetylenic and silyl moieties such as 158, 160, and 162. But-3-ynylmethylphenylsilane does not give any positive result for CO incorporation. Regioselectivity for the silylformylation is completely reversed from the one in the standard silylformylation discussed in Section 11.14.2.2. A bulky /ft7-butyl group in 162 (R = Bu ) plays an... [Pg.490]

A hydrosilyloxy moiety also works as a directing group for the intramolecular silylformylation regardless of terminal and internal alkynes (Table 9)7 ... [Pg.492]

A second example of intramolecular silylformylation involves reactions of terminal and internal alkynes linked to a dimethylsiloxy group, as depicted in Eq. (50).125... [Pg.240]

Although the regioselectivity for the silylformylation of 1-alkynes is excellent, that of internal alkynes is low except for 2-alkynoates (vide supra). Also, in the reactions of 1-alkynes, the silyl group is always delivered to the terminal position and the formyl to the C-2 position, thus it is impossible to synthesize 3-silyl-2-alkenals, which requires opposite regioselectivity. Intramolecular directed reactions can circumvent these limitations and expand the scope of the silylformylation of alkynes. [Pg.1778]


See other pages where Terminal alkynes intramolecular silylformylation is mentioned: [Pg.875]    [Pg.162]   
See also in sourсe #XX -- [ Pg.11 ]




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Alkynes silylformylation

Intramolecular silylformylation

Intramolecular silylformylation alkynes

Silylformylation

Silylformylations intramolecular

Terminal alkynes

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