SALIERES1*

Controlling attosecond electron wavepackets and soft x-ray pulses represents a formidable challenge of general implication to many areas of science1-4. A strong laser field interacting with atoms or molecules drives ultrafast intra-atomic/molecular electron wavepackets on a subfemtosecond timescale, resulting in the emission of attosecond bursts of extreme ultraviolet (XUV) light5,6. Controlling the intra-atomic/molecular electron dynamics allows steering the attosecond emission7,8. Here we perform a coherent control in linear molecules, where the interaction of the laser-driven 2 electron wavepacket with the core leads to quantum interferences9-12. We demonstrate that these interferences can be finely controlled by turning the molecular axis relative to the laser polarization, i.e. changing the electron recollision angle. The wavepacket Coulombic distortion modifies the spectral phase jump measured in the XUV emission. Our attosecond control of the interference results in an attosecond pulse shaping, useful for future applications in ultrafast coherent control of atomic and molecular processes. High Harmonic Generation in gases13,14 is a spectacular process arising when a strong lase