Stereoselective propargylation mediated by a chiral metal cluster: reactions of [(propargylium)Co2(CO)5{P(OR)3}][BF4] with carbon nucleophiles

Scope and advances in the catalytic propargylic substitution reaction

“…129,130 The method reported was the rst of its kind compared to the so-far-known highly diastereoselective and enantioselective propargylic substitution reaction methods, which used a stoichiometric amount of transition metal complexes. [131][132][133] for the enantioselective reactions with a ketone.…”

Chemistry of Propargyldicobalt Cations Recent Developments in the Nicholas and Related Reactions

“…This can be overcome in selected cases. Nicholas has shown that replacing a CO ligand with a tris(hexafluoroisopropyl) phosphite [P(OCH(CF 3 compromise which allows sufficient reactivity with silyl enol ethers and allylsilanes, giving variable de's, but slowing the enantiomerization process such that the condensation occurs in at least one case with essentially complete retention of configuration at the propargyl site [72]. In the hexacarbonyl substrates, Muehldorf has demonstrated that enantioenriched propargyl alcohol complexes bearing a three carbonyl tether to an electron rich aromatic ring (i.e., 37) undergoes low temperature cyclization to give cyclohexanes with varying degrees of enantiomerically enrichment at the benzylic site [73].…”

Stoichiometric applications of organotransition metal complexes in organic synthesis

“…The complexes 28 are formed as easily separable diastereoisomers from chiral alcohol precursors; reaction of a single diastereoisomer with silyl enol ethers proceeds with complete retention of configuration at the propargylic carbon atom (Scheme 23). 57 Propargylic cations are presumably implicated in the a to B epimerization of C-1-alkynyl substituted pyranose derivatives 2 9 via their dicobalt hexacarbonyl derivatives (Scheme 23).…”