Reactions of Main Group Metal Compounds

The functionalized enamine 85 was prepared by coupling of propargyl bromide with the a-stannyl enamide 84 using AsPh3 as a ligand and CuCl as an additive [25]. 

The cyanoallene 88 was prepared by the reaction of the carbonate 86 with trimethylsilyl cyanide (87). hi the presence of excess 87, the dicyanated product 

89 was obtained in high yield [26]. Treatment of the chiral (R)-disilanyl ether 

90 with the Pd catalyst coordinated by hindered isonitrile 93 (XVII-6) yielded the allenylsilane 91, which was trapped with cyclohexanecarboxaldehyde to give yn-homopropargylic alcohol 92 with 93.3 % ee with high diastereoselectivity [27]. 

No cross-coupling of propargyl compound 94 with an excess of Et2Zn occurred. Instead, a nucleophilic propargyl species is generated by umpolung and reacts with benzaldehyde to give 95 [28], 

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