Coupling of silyl imine and aldehyde
This is a Peterson olefination, specifically this one is from the synthesis of Roseophilin published in J. Am. Chem. Soc. (2001) 123 8509. The LDA deprotonates next to the silicon as both it and the adjacent imine stabilise the anion.

The Wikipedia page gives a good summary of the mechanism and why an acidic work up is used in this case to give the required double bond geometry (Wikipedia).


  


(Image from www.chem.wisc.edu)