Of course, the CDS is more attractive since this could realize [4+2+1] reactions with a broad scope of substrates, if succeeded. However, the SDS is also significant since the special [4+2+1] products from this strategy could be useful. The SDS could be more powerful if a special intermediate group required in the substrates for the [4+2+1] reaction can have rich chemistry of transformations, which in turn will significantly access many other useful skeletons. For example, our previous [4+2+1] reaction of in situ generated ene/yne-ene-allenes with CO belong to the SDS (Scheme 1b). In this reaction, the traditional dienes are changed to ene-dienes, where allene is regarded as an intermediate group. The allene is critical to provide additional coordination to help this [4+2+1] reaction. We can envision that this intermediate group can be further transformed to other useful groups, which is our ongoing research. Here we report a serendipitously discovered [4+2+1] reaction of cyclopropyl-capped diene-ynes/diene-enes with CO, which also belongs to the SDS (Scheme 1c).