Alkyne derivatives hydroformylation

In a similar way as described for the hydroformylation, the rhodium-catalyzed silaformylation can also be used in a domino process. The elementary step is the formation of an alkenyl-rhodium species by insertion of an alkyne into a Rh-Si bond (silylrhodation), which provides the trigger for a carbocyclization, followed by an insertion of CO. Thus, when Matsuda and coworkers [216] treated a solution of the 1,6-enyne 6/2-87 in benzene with the dimethylphenylsilane under CO pressure (36 kg cm"2) in the presence of catalytic amounts of Rh4(CO)12, the cyclopentane derivative 6/2-88 was obtained in 85 % yield. The procedure is not restricted to the formation of carbocycles rather, heterocycles can also be synthesized using 1,6-enynes as 6/2-89 and 6/2-90 with a heteroatom in the tether (Scheme 6/2.19). Interestingly, 6/2-91 did not lead to the domino product neither could 1,7-enynes be used as substrates, while the Thorpe-Ingold effect (geminal substitution) seems important in achieving good yields. 

In a similar manner, polymers with unsaturated chains or side chains can be converted to polyamines [66-69]. Conjugated diolefins usually undergo hydroformylation with low selectivities [70]. Mostly hydrogenation of at least one double bond occurs and mixtures of various saturated and unsaturated amines and diamines are obtained [71]. Similar to alkenes also alkynes may serve as unsaturated compounds in hydro aminomethylation reaction sequences. Although synthetically attractive, only a few investigations towards hydroformylation and hydroaminomethylation of alkynes in the presence of N-nuclcophilcs are known. Usually a preferred transformation to furanonic derivatives is observed under hydroformylation conditions [27]. 

In contrast to hydroformylation of olefin derivatives, the addition of carbon monoxide and trialkylsilane to alkynes gives carbon-centered silanes exclusively when catalyzed by, for example, rhodium and Rh-Co carbonyl clusters [153, 154] and Rh2(pfb)4 (pfb = perfluorobutyrate) (eq. (13) [153]). 

Hydroformylation reactions that are mediated by rhodium catalysts can also be incorporated into cascade sequences. The zwitterionic rhodium complex 694 promotes a tandem cyclohydrocarbonylation/CO insertion reaction producing pyrroli-none derivatives that contain an aldehyde functional group in good yields (01JA10214). In one example, exposure of a-imino alkyne 693 to catalytic quantities of 694 and (PhO)3P under an atmosphere of CO and H2 at 100 °C produced pyrrolinone 695 in 82% yield (Scheme 113). A variety of alkyl substitutents can be tolerated in this reaction. 

Silylformylation of olefins and alkynes can be regarded as the silicon version of hydroformylation. The reaction involves the concomitant introduction of a silyl group, derived from a hydrosilane, and a formyl group derived from insertion of carbon monoxide, thus producing functionalized olefins and dienes, which are useful synthons. ... 

Somewhat contradictory data were published in 1995 [157] and later in 2003 [158] concerning the regioselectivity of the thioformylation reaction in the presence of CO (Scheme 3.88). The Markovnikov derivatives were obtained after alkyne and CO insertion steps with the RhH(CO)(PPh3)3 catalyst, however, mainly anti-Markovni-kov isomer was formed with Wilkinson complex in the hydroformylation reaction (Scheme 3.89) [146]. The same stereochemistry was found in the reaction of AlkSH [159]. 

Bestmann s ylide 0=C=C=PPh3 as a Cj buUding block (Scheme S.ldO). ) The required substrate was derived by the rhodium-catalyzed addition of acetic acid to a terminal alkyne. For the asymmetric rhodium-catalyzed hydroformylation at 10.3 bar, Landis s (S,S,S)-BDP was used as ligand. After hydroformylation and ring closure, the protecting 0-acetyl group was removed by the effect of an enzyme to finally produce (+)-patulolide C in an overall yield of 49%. 

The catalytic performance of 1 was examined for hydroformylation of alkyne (as a catalyst additive) and methoxycarbonylation of alkyl halide, and 1 is also used as a stoichiometric reagent for an Ni-catalyzed ketone synthesis from alkyl halide. " Heterogeneous catalysts derived from 1 are used for hydrogenation of GO and coal tar pitch, crude oil upgrading, and coal liquefaction (preparation of the pyrrhotite catalyst). An Fe-Ru-Se catalyst dispersed on a glassy carbon-supported Nafion film prepared from 1 is reported to be effective for electro-catalytic oxygen reduction. ... 

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