Propargyl bromide, coupling with

Propanol, 1,3-bis(methylthio)-, 54, 19 Propargyl bromide, coupling with an organocopper reagent, 50, 98... 

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

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... 

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]. 

Buynak et al. reported the synthesis of representative 7-vinylidenecephalosporine derivatives bearing an axial allene chirality (Scheme 4.5) [9]. A chiral allene 24 was prepared stereoselectively utilizing the reaction of an organocopper reagent with propargyl triflate 23, obtained by a diastereoselective ethynylation of the ketone 22 with ethynylmagnesium bromide. Terminally unsubstituted allene 26 was synthesized via bromination of the triflate 23 followed by reduction of the bromide 25 with a zinc-copper couple. 

Among the more exotic cydopropylallenes, the polycyclic hydrocarbons 148 (n= 2, 3) may be cited, which are available by coupling the Grignard reagents 147 with propargyl bromide (116) in the presence of various metal catalysts, Fe(acac)3 leading to the highest yields (Scheme 5.21) [60]. 

In an indium-mediated process, the aromatic substrates 150 (X=Br, I, OTf) can be coupled in the presence of catalytic amounts of a Pd° catalyst with the propargyl bromides 151 to yield the arylallenes 152, the reaction most likely proceeding via an allenylindium intermediate (Scheme 5.22) [62],... 

Propargylallene (l,2-hexadien-5-yne) (23) is the other main product obtained when the allenyl copper reagent 117 is coupled with propargyl bromide (116 see above) (Scheme 5.36) [44, 94]. 

Later, a similar coupling reaction between allyl bromide or cinnamyl bromide with Ar3Bi was reported to provide the coupling products in good yields when the bromides were used in excess (Scheme 50) [65]. Under the same reaction conditions, arylation of propargyl bromide also proceeded to provide arylated allenes in moderate yields (Scheme 51) [65]. 

Scheme 51 Cross-coupling reaction of Ar3Bi with propargyl bromide...

Coupling of Propargyl Bromide with (he Grignard Derivative of the O-Protected Propargyl Alcohol in the Presence of Copper(I)Chloride. Synthesis or 2 -Pentadiyn-l-ol... 

Bromopyrimidine and l-bromo-2-butyne reacted to give the butadienyl-pyrimidine derivative in 92% yield, while the sequential coupling of propargyl bromide and l-bromo-2-butyne with 2,5-dibromopyridine gave the expected product in 65% (7.59.), the first allene moiety being introduced into the more reactive 2-position, and the second allene attached to position... 

Assembly of the subunits began with the Nozaki-Kishi coupling reaction of iodoacetylene 13 and aldehyde 12, in the presence of CrCl2/NiCl2, to provide propargylic alcohol 23, with 3 1 dr at C7 (Scheme 3). The four-step conversion to bromide 24 was followed by the enolate alkylation of methyl ketone 14. 

The indium-catalyzed coupling of propargyl bromide with a variety of imines and nitrile A-oxides affords the corresponding propargylated products in high yields under mild conditions (Scheme 64).261... 

Allenylindium reagents, generated in situ from the reaction of indium with propargyl bromides, can be employed as effective cross-coupling partners in palladium-catalyzed reactions with a variety of organic electrophiles to produce substituted allenes, polyallenes, unsymmetrical bisallenes in excellent yields (Table 22).358... 

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