boost converter circuit simulation in LTSpice
Could you please explain why the V(R1) is not 2V?


Because you are not operating in "continuous mode". A boost switcher like this has two main modes of operation; continuous and discontinuous mode. You are operating in discontinuous mode and the simple formula you believed would tell you the story of the output voltage is no longer accurate.

Read the wiki article you linked and notice the two modes of operation mentioned. Notice also how in discontinuous mode the ratio of Vout to Vin is: -

\$1 + \dfrac{V_{IN} D^2T}{2 L I_{OUT}}\$

Try lowering your output resistance significantly to remedy this because, as the wiki article points out, discontinuous mode.....


  ..... commonly occurs under light loads.