Formylation of alkenes

Formylation of alkenes can be accomplished with N-disubstituted formamides and POCl3. ° This is an aliphatic Vilsmeier reaction (see 11-15). Vilsmeier formylation can also be performed on the ot position of acetals and ketals, so that hydrolysis of the products gives keto aldehydes or dialdehydes ... 

Even if hydrides of transition metals play an important role as intermediates in catalytic processes such as hydrogenation and hydro-formylation of alkenes and the Fischer-Tropsch reaction,71 in order to follow with the bioinorganic subject, we refer to the interconversion process ... 

This sequence of steps is an important part of the mechanism of the hydro-formylation of alkenes (oxo reaction), to be discussed in Section 31-4B, and also is related to the carbonylation reactions of boranes discussed in Section 16-9G. 

The silylcarbonylation of alkenes catalyzed by Co2(CO)s giving homologous silyl enol ethers was reported by Murai and coworkers in 1977 as a silicon version of hydro-formylation of alkenes, and developed as a unique synthetic method302-304. Although... 

Carbonylation (the addition of carbon monoxide to organic molecules) is an important industr process as carbon monoxide is a convenient one-carbon feedstock and the resulting metal-acyl cor plexes can be converted into aldehydes, acids, and their derivatives. The 0X0 process is the hydr formylation of alkenes such as propene and uses two migratory insertions to make higher val aldehydes. Though a mixture is formed this is acceptable from very cheap starting materials. 

Formylation of alkenes can be accomplished with A-disubstituted formamides... 

A variety of pyridine ring syntheses stem from Vilsmeier formylation of alkenes, enamines, vinyl ethers, ketones, and related systems followed by a separate cyclization of the derived salts with ammonium chloride or acetate.49... 

Formylation of trienes. Formylation of alkenes and dienes with the Vilsmeier reagent has been of limited value, but Dutch chemists find that formylation of trienes can be useful. Formylation occurs mainly at Ci (equation I) the reaction has been used for synthesis of dehydrocitral from 2,6-dimethyl-2,5-heptadienone (equation II). ... 

NaY zeolite containing [Rhc(CO)i ] has been shown to be a catalyst for the hydro-formylation of alkenes in the liquid phase at 80 C and 80 bar. [38] The catalysts were selective for the formation of butyraldehydes, with a n- to uo-butyraldehyde ratio similar to that shown by mononudear rhodium carbonyls in solutions. [119] The catalyst was also tested for the hydroformylation of nonconjugated dialkenes and produced mainly dialdehydes. [38] The catalyst was recovered after use by decantation and reused with only a small loss in activity. 

Formylation of Alkenes. Both activated and unactivated alkenes undergo electrophilic attack by (2). Reaction at terminal positions is preferred. Styrene derivatives give cinnamaldehydes enamines and aryl polyenes - react at terminal positions (eq 5). 

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