36 for spectra of isoelectronic d7 Co11 species).It is less clear from the spectra in Figure 5 how the weak IR band on the side of the e mode is polarized. This uncertainty is completely removed by the difference spectra illustrated in Figure 6. These spectra, obtained by computer subtraction, show that this weak band, arrowed, is polarized in the same direction as the e mode and opposite to the a! mode. This supports our original assignment of this band to a matrix splitting of the e mode (qv). ConclusionsThese experiments have finally ended the search for the elusive Mn(CO)5 radical and it is clear that earlier attempts12 to synthesize Mn(CO)5 in matrices were unsuccessful.37 Mn(CO)5 has (35) Alexander,

state, 29, predominant formation of the cis decalin 27 would be expected. As shown for 3 in diagram 21, the Ci equatorial hydrogen bond in 26 is perpendicular to the cyclopropane bond which is adsorbed on the catalyst. Thus, the formation of the olefin 30 could occur by a process similar to that described for the formation of 22. While the product stereochemistry obtained from the hydrogenation of 30 is not available, it has been reported that the hydrogenation of the demethyl compound 31 over platinum in acetic acid at room temperature and 1 atm gives a 60:40 mixture of the cis and trans decalins 32 and 33.18 Further work is currently underway in an attempt to establish whether the hydrogenolysis of cyclopropyl compounds such as 3 and 26 does, indeed, take place through an olefin intermediate as proposed here.

No abstract

No abstract

bvans-2-Ethynyl substituted alcohols can be obtained by treatment of epoxides with ether-stabilised methyl ethynyl alanes; a cis analogue, obtained by oxidation and stereoselective reduction, has been converted into the corresponding cis ring-fused methylene lactone.