Lithium, beryllium and boron aren't produced in (normal) stellar nucleosynthesis - instead, three atoms of helium fuse to form carbon (the triple-alpha process - two helium nuclei fall apart again almost instantly). But the necessary conditions only arise late in the lifetime of a star, when it has stopped burning hydrogen to helium and instead burns helium to heavier elements.
In massive stars there's a catalytic cycle with carbon, nitrogen and oxygen called the CNO cycle, during main sequence evolution - the equilibrium state is very nitrogen rich (which is why massive stars are usually nitrogen overabundent and carbon and oxygen depleted), but in the latter states of the stellar lifetime the balance shifts as helium burning forms carbon - visible in the spectra of carbon-type Wolf-Rayets - while adding a helium nucleus to carbon gives you oxygen. Nitrogen then dips and becomes somewhat underabundent.
Side branches of the CNO cycle are responsible for some other elements, while successively adding helium nuclei to oxygen gives things like silicon, magnesium, calcium (alpha-process elements) and iron. The heavy elements all require neutron capture in red (super)giants.