Ring expansion with heterocumulenes

Heterocumulenes X=C=Y insert themselves into one and (to a lesser degree) both Si—N bonds of 1,3,2-diazasilacyclopentanes (112) with expansion of the ring, usually at — 50°C to RT. This is followed by transformation to other products generally in fair to high yields (Scheme 8). Carbonyl compounds and a diphosphetane derivative react similarly <91J0M(419)9>. 

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