Alkylidenecyclopropanes, tethered

The transition metal-catalyzed addition of alcohols to unsaturated systems has not been widely investigated. Reports on addition of alcohols to 1,3-diene [24] or allene [25] have appeared but have very limited scope. We recently reported the palladium/benzoic acid-catalyzed inter- and intramolecular addition of alcohols to alkynes in which various acyclic and cyclic allylic ethers are produced [26], The Pd-catalyzed addition of alcohols to alkylidenecyclopropanes proceeds smoothly providing a powerful tool for synthesis of allylic ethers [27a]. An intramolecular version of the hydroalkoxylation has been demonstrated in which the phenol-tethered alkylidenecyclopropanes undergo facile cyclization to give exomethylene products [27b],... 

An example of a rhodium(I)-catalyzed cycloisomerization of nitrogen-tethered indole-alkylidenecyclopropanes 13 was reported allowing for ready access to azepinoindole derivatives 14, which are tetrahydro-P-carboline homologs (13CEJ13668). 

A synthesis of pyrrolo[l,2-fl]indoles via a thermally induced ring opening and cycliza-tion reaction of aniline-tethered alkylidenecyclopropanes with aldehydes has been reported (Scheme 38). ... 

The development of an Rh-catalysed [3 -f 2 -1- l]-carbocyclization of carbon- and heteroatom-tethered alkenylidenecyclopropanes with carbon monoxide for the stereoselective construction of cw-fused bicyclohexenones has been reported with ring opening of alkylidenecyclopropane proceeding through an Rh(III)-trimethylenemethane complex that undergoes rate-determining carbometallation (Scheme 149). 0... 

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