Homopropargyl amines, synthesis

Scheme 26 Synthesis of 2-aikyl-4-halo-1 -tosyl-1,2,5,6-tetrahydropyridines from A-tosyl homopropargyl amine and aldehydes using FeX3 as promotor...

Functionalized piperidines 165 and 166 for the synthesis of enantiopure homokainoids have been generated in excellent yields via a Rh-catalyzed cyclohydrocarbonylation reaction on both homoallylic amines 167 and homopropargylic amines 168 <07JOC9418>. 

The [2 -I- 2 -I- 2] cycloaddition reaction was used successMly in the synthesis of the sesquiterpene alkaloid illudinine (Scheme 2.6) [5], The terminal diyne 27 bearing a gm-dimethyl group in the backbone successfully undergoes a nickel-catalyzed cycloaddition reaction with protected homopropargyl amine 28 to afford cycloadduct 29. This intermediate (29) was converted successfully to the natural product illudinine 30 in five simple steps. 

Enantioselective synthesis of homopropargyl amines can be effected through copper-catalysed reaction of an allenyl boron reagent with aldimines. The first nucleophilic allylation of r-electrophiles by allylboron reagents has been achieved enantioselectively using a chiral rhodium catalyst (Scheme an allylrhodium intermediate has been implicated. Similar additions of R CH=CR BF3K have also been reported. ... 

The reaction of homopropargylic ketones with primary amines is an excellent method for the synthesis of highly substituted pyrroles. As shown for one example in Scheme 12.16, the yields often are better with the silver catalyst.33... 

This section covers cyclizations to the pyrrole nucleus catalyzed by other metals (Ti, Mn, Ru, Pd, Pt, Zn, In). Dembinski and co-workers used zinc(II) chloride as ligand-free catalyst for the microwave-assisted cyclization of homopropargyl azides 26 to afford substituted pyrroles 27 (Scheme 8) [62]. A similar methodology for the synthesis of 2,4,5-trisubstituted pyrroles was described by Driver et al. employing substituted 1-azidobuta-l,3-dienes in a cyclization reaction using catalytic amounts of zinc(ll) iodide [63]. A three-component zinc-catalyzed one-pot cyclization of aromatic and aliphatic propargylic acetates, silyl enol ethers, and primary amines to substituted pyrroles has been described by Zhan et al. The reaction sequence includes propargylation of the silyl enol ether, amination, 5-exo-(7ig-cyclization, and isomerization [64]. Hiroya and co-workers have shown... 

Intramolecular additions of alcohols or amines to olefins are recognized as useful methods to provide heterocyclic compounds. Kozmin and Zhang have achieved a gold-catalyzed synthesis of heterobicyclic alkenes by double cyclization of alcohols or sulfonamides which have a 1,5-enyne moiety [175]. As a typical example, unsaturated alcohol (95) is smoothly converted to 6-oxabicyclo[3.2.1]octane (96) in 90% yield using a 5 mol% of AuCls catalyst (Scheme 18.34). Cyclic ethers are also available from homopropargylic ethers with pendant alcohols through gold-catalyzed... 

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