  We consider the $S=1/2$ Heisenberg model with nearest-neighbor interaction
$J$ and an additional multi-spin interaction $Q_3$ on the square lattice. The
$Q_3$ term consists of three bond-singlet projectors and is chosen to favor the
formation of a valence-bond solid (VBS) where the valence bonds (singlet pairs)
form a staggered pattern. The model exhibits a quantum phase transition from
the N\'eel state to the VBS as a function of $Q_3/J$. We study the model using
quantum Monte Carlo (stochastic series expansion) simulations. The N\'eel-VBS
transition in this case is strongly first-order in nature, in contrast to
similar previously studied models with continuous transitions into columnar VBS
states. The qualitatively different transitions illustrate the important role
of an emerging U(1) symmetry in the latter case, which is not possible in the
present model due to the staggered VBS pattern (which does not allow local
fluctuations necessary to rotate the local VBS order parameter).
