| Summary: | Derivatization of spirooxindole having triazole and ferrocene units was achieved by the [3 + 2] cycloaddition (32CA) reaction approach. Reacting the respective azomethine ylide (AY) intermediate generated in situ with the ethylene derivative produced novel asymmetric cycloadducts with four contiguous asymmetric carbons in an overall high chemical yield with excellent regioselectivity and diastereoselectivity. X-Ray single-crystal structure analyses revealed, with no doubt, the success of the synthesis of the target compounds. The 32CA reaction of AY <b>5b</b> with ferrocene ethylene <b>1</b> has been studied within MEDT. This 32CA reaction proceeds via a <i>two-stage</i> <i>one-step</i> mechanism involving a high asynchronous transition state structure, resulting from the nucleophilic attack of AY <b>5b</b> on the β-conjugated position of ferrocene ethylene <b>1</b>. The supernucleophilic character of AY <b>5b</b> and the strong electrophilic character of ferrocene ethylene <b>1</b> account for the high polar character of this 32CA reaction. Further, Hirshfeld analyses were used to describe the molecular packing of compounds <b>4b, 4e, 4h</b> and <b>4i</b>.
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