2-Propenal 1- alkynylation

A study of the regioselectivity of the 1,3-dipolar cycloaddition of aliphatic nitrile oxides with cinnamic acid esters has been published. AMI MO studies on the gas-phase 1,3-dipolar cycloaddition of 1,2,4-triazepine and formonitrile oxide show that the mechanism leading to the most stable adduct is concerted. An ab initio study of the regiochemistry of 1,3-dipolar cycloadditions of diazomethane and formonitrile oxide with ethene, propene, and methyl vinyl ether has been presented. The 1,3-dipolar cycloaddition of mesitonitrile oxide with 4,7-phenanthroline yields both mono-and bis-adducts. Alkynyl(phenyl)iodonium triflates undergo 2 - - 3-cycloaddition with ethyl diazoacetate, Ai-f-butyl-a-phenyl nitrone and f-butyl nitrile oxide to produce substituted pyrroles, dihydroisoxazoles, and isoxazoles respectively." 2/3-Vinyl-franwoctahydro-l,3-benzoxazine (43) undergoes 1,3-dipolar cycloaddition with nitrile oxides with high diastereoselectivity (90% de) (Scheme IS)." " ... 

Alkenyl and alkynyl isocyanates have been prepared from amines and various car-bonylating agents. 3-Isocyanato-propene 416 was obtained either with diphosgene and activated charcoal by heating in ethyl acetate [264] or by using CO2 [276]. 

Ir(i) and Ir(iii) alkynyls have been prepared by Osakada et al. by the reaction of alkynes with tr-allyl complexes. The reaction of HC=CPh with the Ir(l)-7r-allyl complex [Ir(CO)(PPh3)2(77 -CH2CHCH(Ar))] 427 gives a mixture of /ra t-[Ir(C CPh)(CO)(PPh3)2] 428 and /ra r,/ra j-[IrH(CO)(C=CPh)2(PPh3)2] 429 accompanied by the liberation of 1-Ar-l-propene (Scheme 48). The two alkynyl derivatives were authenticated by X-ray diffraction analyses which confirmed SQP and OCT geometries, respectively (Figure 36). 

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