Cycloaddition and cycloreversion reactions of a monomeric Ti(IV) oxo complex with terminal and internal alkynes. A reversible oxametallacyclobutene/hydroxoacetylide interconversion

Article abstract of DOI:10.1021/ja00124a036

The synthesis and structure of Cp*₂Ti(O)(pyr) (Cp* = η⁵-C₅Me₅; pyr = pyridine) (1) were described recently. We report here on the [2 + 2] cycloaddition of 1 with terminal alkynes and yhe novel rearrangement of the resulting oxametallacyclobutenes to hydroxoacetylide complexes. in at least one case the arrangement is reversible, and we have obtained information on its mechanism. We have carried out experiments designed to investigate the mechanism of the oxametallacycle-to-hydroxoacetylide rearrangement.