Neue synthesen und reaktionen ungesättigter heterotitanacyclen
作者:Stefan Dürr、Udo Höhlein、Rainer Schobert
DOI:10.1016/0022-328x(93)80460-s
日期:1993.10
fragment by carbon (formation of vinylenic carbonates and the thia-derivatives of these) or by further heteroatoms like boron or phosphorus (formation of boroles and phosphoric acid derivatives), thus retaining the cyclofunctionality. Alternatively, some of the new chelate complexes can be readily CC-chain-lengthened via a deprotonating/alkylating sequence, leaving the metallacycle unaffected.
The first method for the synthesis of the title compounds has been established involving a stereoselective electrochemical diacylation process. The cathodic reductions of monothiobenzils in an aprotic medium, under constant potential, in the presence of twofold molecular amounts of aroyl chlorides provide previously unknown (Z)-α-benzoyloxy-β-benzoythiostilbenes in high to quantitative yields.