Construction of Spiro[4.5]decanes via Annulations of Azadienes with Nazarov Reagent and DFT Studies

A NaH-promoted domino reaction between azadiene bearing an indene moiety with Nazarov reagent was developed. A variety of spiro[4.5]decane derivatives were obtained via [4+2] cycloaddition with good yields and high diastereoselectivity. The domino strategy benefited from mild reaction conditions and very broad substrate scope. Furthermore, a gram-scale experiment and a transformation of the product were carried out. Lastly, density functional theory (DFT) calculations have been performed to verify the proposed reaction mechanism and analyze the observed diastereoselectivity.

Automated summary

We developed a NaH-promoted domino reaction between an azadiene bearing an indene moiety and a Nazarov reagent, leading to the synthesis of various substituted spiro[4.5]decane derivatives with good yields and high diastereoselectivity via [4+2] cycloaddition. The reaction conditions are mild and exhibit broad substrate scope. Furthermore, gram-scale experiment and transformation of the product were successfully carried out. Finally, DFT calculations were performed to confirm the proposed reaction mechanism and analyze the observed diastereoselectivity.