F-Butylacetylene

Additional evidence that reaction paths analogous to the reactions of mononuclear and dinuclear rhodium complexes exist on palladium is shown by the effect of triphenylphosphine on the stereoselectivity of the hydrogenation of di-f-butylacetylene (DTBA). In the absence of PPhs but on a highly dispersed... 

Propargyl halides have been used by Campbell [25] and by Banigan [26] to prepare acetylenic hydrocarbons. For example, Banigan prepared di-f-butylacetylene by reaction of methylmagnesium bromide with r-butyl-ethynyldimethylchloromethane [26]. However, 10% of the final product was an unidentified compound. Meyers [27] tentatively identified... 

Lithium organocuprates. House et al. have found that certain undesirable side reactions in the preparation of lithium organocuprates can be minimized by use of this complex rather than commercial cuprous bromide itself, which apparently contains some impurities. The complex is readily prepared in 90% yield from (CHslj S and CuBr. It is insoluble in ether, hexane, acetone, methanol, and water, but dissolves in several solvents in the presence of excess (CH3)2S. Thus a solution of the complex in ether and (CH3 >2 S is used the excess sulfide is readily separated from reaction products. The soluble copper reagent t-BuC=CCu can also be used instead of CuBr, but the precursor, f-butylacetylene, is expensive. The use of the complex was illustrated for reactions of (CH3)2CuLi and (CH2==CH)2CuLi. 

Reaction of 1-Alkyne with Diethyisiiane. The reaction of f-butylacetylene with diethyisiiane in the presence of KF/AI2O3 at 303 K affords the silylacetylene (112). 

Okano, Y Masuda, T. Higashimura, T. Polymerization of f-butylacetylene by group 6 transition metal catalysts Geometric structure control by reaction conditions. Polym. J. 1982,14,477-483. 

The stereochemistry for migratory insertion of alkynes has led to effective methods for creating each of the different stereoisomers of deuterated terminal alkenes. Eq. 12.51 shows a sequence of reactions involving f-butylacetylene. Due to the 100% stereoselective syn addition of the Zr-D bond, only one product is obtained. 

Benzyne complexes shown in Scheme 16.5 form a similar octahedral structure as shown in Figure 16.7. The bond length of C=C of benzyne is 1.3555 A, it is shorter than the other C=C bonds (1.372 A—1.411 A). The benzyne complex is a white solid, very liable to air, but it is stable for several months at room temperature under an inert gas atmosphere. It reacts with water at 20 °C and the 7r-coordination changes to two c-bonds of phenyl and OH bond [28]. Ruthenium phosphine reacts with f-butylacetylene to afford a ruthenium carbene (Br2(PPh3)2Rn=C=CH(t-Bu)) via an acetylene-7r-complex as shown in Figure 16.7. 

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