Amine From alkyne

Here lies the first roadblock. Although the large scale preparation of some related vinyl derivatives such as enol ethers from acetylene itself has been used in the chemical industry for years, these syntheses usually require catalysis by mercuric salts and yields are often quite poor. Similarly, enamines have been claimed to be intermediates in the synthesis of amines from alkynes, but this process also requires mercuric ion catalysis. ... 

Synthesis of chiral allylic amines from alkynes and A -sulfonylaldimines involves reductive activation of the alkynes. The metal atom of iridacyclopropene intermediates also gathers the sulfonylimine as a bidentate ligand prior to bonding reorganization within the coordination sphere. The absolute stereochemical sense is governed by the chiral ligand employed (such as a member of the BIPHEP series). 

Chiral allylic amines constitute key synthetic intermediates, auxiliaries, and resolving agents in the synthesis of both natural and nonnatural products. In 2004, Jamison and Patel reported the first highly enantioselective catalytic synthesis of allylic amines from alkynes, imines, and organobo-ranes such as triethylborane. Catalysed by a chiral complex derived from Ni(cod)2 and chiral ferrocenylphosphine [R)-27, this novel three-component process provided chiral tetrasubstituted allylic amines in good yields in one-pot (Scheme 4.27). These products were obtained in moderate to very good enantioselectivities of up to 89% ee. Both symmetrical and... 

Alkenylzirconium reagents generated from alkynes and the Schwartz reagent react with aldimines under mild conditions in the presence of [RhCl(COD)]2 to give homoallylic amine derivatives (Equation (63)).418... 

Similar to the CuOTf/PyBox system, the CuBr/QUINAP system also gave high enantioselectivities of the three component reactions to construct propargyl amines from aldehydes, amines, and alkynes (Scheme 5.6). In this system various aldehydes including aromatic aldehydes and aliphatic aldehydes could be used and a wide range of chiral propargyl amines were prepared in good yields and enantioselectivities. Mechanistic studies showed that the dimeric Cu/QUINAP complex is the catalytically active species that differs from the previous reaction. 

Solvent-free conditions were used by Tanaka et al. in their assays to obtain intermolecular reactions from alkynes and anilines. The chosen catalyst was [AuMe(PPh3)] with an acidic promoter [92]. Reaction, whose effectiveness was greater in the case of aromatic amines, proceeded via Markovnikov by amine electrophilic attack of the alkyne in a similar way to the methanol addition proposed by Teles (see Section 2.1.3.2) and provided high yields and TONs. 

Asymmetric versions of these transformations can be carried out when resolved EBTHI zirconaaziridines are used (Eq. 15). The allylic amine products (Table 3) resulting from alkyne insertion followed by workup are not only geometrically pure, but also enantiomerically enriched the ee is high for a variety of substrates [18]. A phenyl substituent (R1) on the zirconaaziridine... 

Further transformations of such zirconacycles are possible before the organic product is removed from the metal center. Buchwald followed the insertion of an alkyne into a zirconaaziridine with the insertion of CO to obtain substituted pyrroles (in a single pot at ambient temperature) in moderate to good yields. A diverse array of substituents can be introduced by varying the amine and alkyne examples are shown in Table 4. The reaction is tolerant not only of various alkyls and aryls, but also of thiophenyl, furyl, and pyrrole substituents, and can create 2,2 -bipyrroles (see Table 4). It does, however, require high CO pressure (as much as 1,500 psi can be necessary) [56]. 

Benzylic boronic esters [52]can be obtained from bromomethyl boronic esters and aryl or vinyl stannanes [53]. Alkyl and vinyl boronic esters are accessible through hydroboration of alkynes with dialkylboranes followed by oxidation with acetaldehyde [43]. Alternatively, vinylboronates can be obtained directly from alkynes in a reaction -with catecholborane without a subsequent oxidation step [53]. Further diversification in the boronic acid derivatization is achieved by binding the boronic acids bearing another derivatizable functional group (for instance an amine) to suitable polymeric supports. The modified boronic acid may then be... 

From ortho-Halo Aryl-Amines and Alkynes... 

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