How does "gsub" handle spaces?

I have a character string "ab b cde", i.e. "ab[space]b[space]cde". I want to replace "space-b" and "space-c" with blank spaces, so that the output string is "ab[space][space][space][space]de". I can't figure out how to get rid of the second "b" without deleting the first one. I have tried:

gsub("[\\sb,\\sc]", "", "ab b cde", perl=T)

but this is giving me "a[spaces]de". Any pointers? Thanks.

Edit: Consider a more complicated problem: I want to convert the string "akui i ii" i.e. "akui[space]i[space]ii" to "akui[spaces|" by removing the "space-i" and "space-ii".