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Carbonylative couphng

Kahn BE, Rieke R (1988) Carbonyl couphng reactions using transition metals, lanthanides, and actinides. Chem Rev 88 733... [Pg.153]

In the first step, a resin-bound secondary amine is acylated with bromoacetic acid, in the presence of N,N-diisopropylcarbodiimide. Acylation of secondary amines is difficult, especially when coupHng an amino acid with a bulky side chain. The sub-monomer method, on the other hand, is facilitated by the use of bromoacetic acid, which is a very reactive acylating agent Activated bromoacetic acid is bis-reactive, in that it acylates by reacting with a nucleophile at the carbonyl carbon, or it can alkylate by reacting with a nucleophile at the neighboring ah-phatic carbon. Because acylation is approximately 1000 times faster than alkylation, acylation is exclusively observed. [Pg.4]

The direct preparation of arylboronic esters from aryl halides or triflates now allows a one-pot, two-step procedure for the synthesis of unsymmetrical biaryls (Scheme 1-41) [147]. The synthesis of biaryls is readily carried out in the same flask when the first coupling of the triflate with diboron 82 is followed by the next reaction with another triflate. The synthesis of naturally occurring biflavanoids and the couphng of N-(phenylfluorenyl)amino carbonyl compounds to polymeric supports are reported [154]. [Pg.36]

Our study on the synthesis, structure and catalytic properties of rhodium and iridium dimeric and monomeric siloxide complexes has indicated that these complexes can be very useful as catalysts and precursors of catalysts of various reactions involving olefins, in particular hydrosilylation [9], silylative couphng [10], silyl carbonylation [11] and hydroformylation [12]. Especially, rhodium siloxide complexes appeared to be much more effective than the respective chloro complexes in the hydrosilylation of various olefins such as 1-hexene [9a], (poly)vinylsiloxanes [9b] and allyl alkyl ethers [9c]. [Pg.293]

We have explored two types of carbon-carbon bond forming reactions operated under almost neutral conditions. Both reactions are initiated by the formation of an H-Rh-Si species through oxidative addition of a hydrosilane to a low-valence rhodium complex. Aldol-type three-component couphngs are followed by the insertion of an a,yS-unsatu-rated carbonyl compound into a Rh-H bond, whereas silylformylation is accomplished by the insertion of an acetylenic moiety into a Rh-Si bond. [Pg.126]

The tnCl3-mediated, tin(lV)-catalyzed Prins-type couphng of allylphenols with carbonyl compounds gives oxepanes as a mixture of diastereomers (Scheme 8.119)... [Pg.371]

To accelerate aUylation with aUylstaimanes, addition of a Lewis acid is often required, because coordination of the Lewis acid to the carbonyl can enhance the electrophilicity of the substrate and facilitate the couphng reaction. Since Yamamoto showed that a nonracemic Lewis acid, chiral (acyloxy)borane (CAB), catalyzed enantioselective allylation [73], chiral Lewis acid catalysts have been extensively developed. Above all, easily available chiral compounds such as BINOL and BINAP have been most frequently used as chiral auxiliaries [74], and enantioselective allylations of C-N double bonds and of carbonyl groups have been achieved [48a, 75]. [Pg.635]

Now the couphng with the add chloride takes place as before though this time we have an aliphatic carbonyl complex. There is no problem with (5-elimination as that would give a ketene. Again, the stereochemistry of the vinyl staimane is retained in the product. [Pg.482]


See other pages where Carbonylative couphng is mentioned: [Pg.79]    [Pg.215]    [Pg.1112]    [Pg.79]    [Pg.215]    [Pg.1112]    [Pg.106]    [Pg.35]    [Pg.411]    [Pg.902]    [Pg.308]    [Pg.286]    [Pg.529]    [Pg.48]    [Pg.1057]    [Pg.260]    [Pg.125]    [Pg.132]    [Pg.133]    [Pg.312]    [Pg.352]    [Pg.772]    [Pg.238]    [Pg.197]    [Pg.106]    [Pg.111]    [Pg.28]    [Pg.199]    [Pg.4106]    [Pg.113]    [Pg.136]    [Pg.138]    [Pg.102]    [Pg.85]    [Pg.185]    [Pg.344]   
See also in sourсe #XX -- [ Pg.380 , Pg.387 ]




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