Bromide propargyl, reaction with

Allenie alcohols (9, 119).1 The reaction of propargylic bromides (1) with aldehydes or ketones can result in allenie alcohols (3) and/or homopropargylic alcohols (4). The selectivity depends on the substitution in 1 and 2 and is also... 

The reaction of a propargylic bromide derivative with Me3SiSnBu3 and CsF gives 3,4-benzocycloocten-l,5-diyne. This is the first example of the highly strained diyne (Equation (116)).287 288... 

A-allylic amines are conveniently prepared in high yields by the reaction of azides with allylindium reagents in the presence of sodium iodide at ambient temperature (Equation (74)).307 Stannylation with tributylchloro-stannane occurs exclusively at the a-carbon, yielding allyltributylstannanes (E, Z)-isomerization of the allylic double bond depends largely upon the substitution pattern on the allylic moiety (Equation (75)).26 Allyl and propargyl bromides react with diphenyl diselenides in aqueous media to give allyl and propargyl selenides (Equation (76)).308 309... 

Propargylic bromides react with a BusSnMgCl reagent generated in situ from BusSnCl and Mg in the presence of a PbBr2 catalyst (Eq. 70) [84]. The reaction can be conducted on terminal acetylenes and acetylenic esters. 

Propargyl bromide reacts with sodium diethyl phosphite to give diethyl 1-propynylphosphonate. Unfortunately, irrespective of the reaction conditions (sodium in refluxing THF or liquid ammonia, K2CO3 in CgHg at 70°C or KF at 60°C without solvent ), complex mixtures containing diethyl 1-propynylphosphonate, 2-propynylphosphonate, and diethyl allenylphosphonate are obtained. 

The reaction between alkyl halides and aluminum metal is the basis of the oldest method for the synthesis of organoaluminum compounds. For example, propargylic bromides react with aluminum in ether giving organoaluminum compounds that on treatment with acetals yield solely a-allenic ethers (equation 1)." However, the reaction of simple alkyl halides with aluminum metal requires a long reaction time. 

As was recently found, the reaction of 1,1-difluoro-propargylic bromides [70] with zinc in THF yield the Wurtz-coupling product exclusively ... 

Allylic, benzylic and propargylic bromides will also react with zinc to give the corresponding organozinc bromides. Reaction with both C—C and C—N multiple bonds has already been shown to provide a potentially useful route to some Olefinic compounds [135]. However, the reaction with terminal acetylenes produces mixtures of mono- and bis-addition products (27) and (28) in low yields [136] (Scheme 57). 

Ojj 1.5323, prepared from phenol, KOH in ethanol and propargyl bromide) was added and the mixture was heated at 60°C for 15 min. It was then poured into 200 ml of ice-water and the reaction products were extracted with diethyl ether. The ethereal extracts were washed with saturated NH Cl solution, dried over magnesium sulfate and then concentrated in a water-pump vacuum. There remained 9.5 g of 3 1 mixture... 

In the first method a secondary acetylenic bromide is warmed in THF with an equivalent amount of copper(I) cyanide. We found that a small amount of anhydrous lithium bromide is necessary to effect solubilization of the copper cyanide. Primary acetylenic bromides, RCECCH Br, under these conditions afford mainly the acetylenic nitriles, RCsCCHjCsN (see Chapter VIII). The aqueous procedure for the allenic nitriles is more attractive, in our opinion, because only a catalytic amount of copper cyanide is required the reaction of the acetylenic bromide with the KClV.CuCN complex is faster than the reaction with KCN. Excellent yields of allenic nitriles can be obtained if the potassium cyanide is added at a moderate rate during the reaction. Excess of KCN has to be avoided, as it causes resinifi-cation of the allenic nitrile. In the case of propargyl bromide 1,1-substitution may also occur, but the propargyl cyanide immediately isomerizes under the influence of the potassium cyanide. 

When perfluoroheptylcopper reacted with propargyl bromide, a violent reaction occurred, and less than 10% of the expected allene was obtained [226] However, when propargyl chlorides or tosylates were used as substrates, the expected allenes were obtained m good yields [227] (equation 156)... 

Another cyclisation involving 4-amino-6-methyl-3-thioxo-l,2,4-tiiazin-5-one 82 is the reaction with propargyl bromide followed by palladium(II) catalysis to yield a [1,2,4] triazino[3,4-f ][l,3,4]thiadiazine 83, or with phenacyl bromide to give 84 <96MI03 96CA(125)195597 96MI04 96CA(125)247767 >. 

Little is known about the tolerance of 1 with unsaturated (poly)halogen compounds. Hydrozirconation of chloroalkenes can lead to competitive cycUzation, and simple reduction of both C=C and C-Cl bonds [98, 222], However addition of 1 to an alkenyl- or propargyl bromide led to the expected product as the sole product of the reaction in excellent yield (Scheme 8-30) [134, 223]. 

Reaction with Propargyl Halides. The indium-mediated coupling of propargyl bromide with a variety of imines and imine oxides afforded homo-propargylamine derivatives in aqueous media under mild conditions.78 Propargylation of glyoxylic oxime ether in the presence of a catalytic amount of palladium(O) complex and indium(I) iodide in aqueous media was also studied (Eq.11.47).79... 

Inclusion of an acetylenic linkage as part of the side chain is apparently consistent with antidepressant activity. Reaction of propargyl magnesium bromide with dibenzocycloheptadieneone leads to carbinol 82. A Mannich reaction with formaldehyde and dimethylamine leads to 83 which, upon dehydration... 

Another recent development in the field of palladium-catalyzed reactions with alkynes is a novel multicomponent approach devised by the Lee group. Starting from a-bromovinyl arenes and propargyl bromides, the assembly ofeight-membered car-bocycles can be realized via a cross-coupling/[4+4] cycloaddition reaction. The authors also presented the combination of a cross-coupling and homo [4+2], hetero [4+2], hetero [4+4] or [4+4+1] annulation leading to various cyclic products [147]. 

Similar reactions occur with all aliphatic halides and the rates of substitution are related to the degree of ionic character of the carbon-halogen bond. For preparation purposes, trityl bromide or propargyl bromide are more convenient than allyl bromide. The compounds obtained are listed in Table XI. They were obtained pure and characterized fully. Zr (allyl) 3Br and Zr(allyl)2Br2 are sufficiently soluble in toluene for polymerizations to be initially homogeneous. Their relative reactivities are listed in Table XI. In all cases hydrogen was used to reduce the molecular weight of the polymer formed. In this respect the polymer derived from Zr (allyl )3Br was more readily modified than that from Zr (allyl) 4, but in order to avoid... 

Also studied was the effect of ether, which behaves as a retarder, on the polymerization. The retardation is most marked with the di- and trihalides and least with the monohalide and Zr (allyl) 4. In fact if large amounts of ether are present from the preparation, Zr(allyl)2Br2 shows hardly any activity at all. To avoid any possibility of contamination by ether, the halides in Table XI were prepared from pure ether-free Zr(allyl)4 in toluene by reaction with propargyl bromide. 

Diterpenoids related to lambertianic acid were prepared by intramolecular cyclization of either an alkene or an alkyne with a furan ring <2005RJ01145>. On heating amine 101 with allyl bromide, the intermediate ammonium ion 102 was formed which then underwent [4+2] cycloadditions in situ to give the spiroazonium bromides 103 and 104 (Scheme 13). These isomers arose from either endo- or co-transition states. The analogous reaction was also carried out with the same amine 101 and propargyl bromide. The products 105 and 106 contain an additional double bond and were isolated in 58% yield. The product ratios of 103 104 and 105 106 were not presented. 

---