Boron compounds carbonylation

Acetone Alkali cyanides, hydrides, metals Aluminum borohydride, carbide, hydride nitride Benzoyl chloride Boron compounds Carbonyls Chlorine Cyanogen Cyanogen bromide Cyanogen chloride... 

The boron-oxygen mesomeric effect described in the previous section explains the lower reactivity of allylic boronates towards carbonyl compounds compared to that of allylic boranes. The use of Lewis acids, however, allows boronate derivatives, including hindered ones, to react at temperatures comparable to the analogous boranes. As described above (see section Mechanism and Stereochemistry ), the most reactive allylic boronates are those with the most electrophilic boron centers.The nucleophilicity of the y-position of an allylic boron reagent (the position that forms the new C-C bond with the aldehyde) is also important to the reactivity of the reagent. For example, allylic boronates with... 

Cross-coupling reactions 5-alkenylboron boron compounds, 9, 208 with alkenylpalladium(II) complexes, 8, 280 5-alkylboron boron, 9, 206 in alkyne C-H activations, 10, 157 5-alkynylboron compounds, 9, 212 5-allylboron compounds, 9, 212 allystannanes, 3, 840 for aryl and alkenyl ethers via copper catalysts, 10, 650 via palladium catalysts, 10, 654 5-arylboron boron compounds, 9, 208 with bis(alkoxide)titanium alkyne complexes, 4, 276 carbonyls and imines, 11, 66 in catalytic C-F activation, 1, 737, 1, 748 for C-C bond formation Cadiot-Chodkiewicz reaction, 11, 19 Hiyama reaction, 11, 23 Kumada-Tamao-Corriu reaction, 11, 20 via Migita-Kosugi-Stille reaction, 11, 12 Negishi coupling, 11, 27 overview, 11, 1-37 via Suzuki-Miyaura reaction, 11, 2 terminal alkyne reactions, 11, 15 for C-H activation, 10, 116-117 for C-N bonds via amination, 10, 706 diborons, 9, 167... 

Grubbs used (4a) to efficiently install functional groups that might otherwise be added via C H activation or allylic oxidation pathways (Scheme 12). Among the breadth of compound types accessible through these cross metathesis strategies were substituted vinyl-phosphonic, boronic, and carbonyl esters, which were synthesized in good to excellent yields. ... 

Bismuth and bismuth compounds Boron and boron compounds Cadmium and cadmium compounds Carbonyle... 

This commoner type of reaction involves the attack of carbon or heteroatom nucleophiles onto carbonyl compounds, by direct or conjugate addition, and onto imines. Because we have just dealt with boranes we shall start with the reaction of allylic boron compounds with such electrophiles. You might strictly not call this nucleophilic attack. 

Mixing trialkylboranes with a, 3-unsaturated carbonyl compounds in the presence of water gives conjugate addition of one of the alkyl groups from the boron. The carbonyl compound can be an aldehyde (R = H) or a ketone (R = alkyl). 

Thus the three-way bridging carbonyl group (rather than the metal atom, as in most other metal carbonyl anions) is the nucleophilic species in the Co3(CO)jo anion (277). The boron compound (CH3)3NBH2OCC03(CO)g (57 Y = (CH3)3NBH2O) had previously (255) been prepared by heating CO2(C0)g with (CH3)3NBH3 in benzene at 60 to 65°C and has been characterized by x-ray crystallography. 

The 1,4-addition of a,)5-unsaturated carbonyl proceeds not only to the double bond but also to the triple bond of unsaturated carbonyl compounds. For example, a c/5-alkene is selectively obtained with an organocopper boron compound as shown in eq. (22.33) [81]. 

Scheme 5.23 Palladium(ll)-catalyzed 1,4-addition of aryl boron compounds to a,p-unsaturated carbonyl compounds, as described by Miyaura and coworkers [73].

It has been shown that /ranj,// a/w,rm 5 -perhydrophenalen-9-ol is obtained from cw,cis -perhydro-96-boraphenalene via the three-migration cyanoborate process in contrast to carbonylation, which yields the cis ,CM, cis-isomer the cis,trans boron compound produces the cis,cis,trans alcohol by either process. ... 

Boron compounds play an essential part in many organic syntheses, from C-O bond breaking in a variety of ethers, esters, and acetals, to asymmetric allylation of carbonyl compounds. Boron... 

In many instances, the scope of the reactions listed above is limited as to the functional groups that are unaffected. Except for aryl-stannanes and arylfluorosilanes, carbonyl functionalities are often not compatible with the reactions. A number of cross-coupling reactions are known of aryl triflates [64 a] and arylfluorosulfonates [64b] with aryl stan-nanes catalysed by Pd(0)-complexes (Stille reaction) [65], aryl zinc chlorides [64b], and aryl boron compounds (boronic acids and esters, Suzuki reaction [66]). Aryl stannates are relatively stable to air and moisture and many funetional groups are tolerated. The coupling reaction using Ar-X/Ar-SnR3 can be accelerated by Cu(I) [67] or Ag(I) [68] catalysis. 

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