Canadian stocks are expected to open mixed on Wednesday as investors turn cautious ahead of the Federal Reserve’s monetary policy announcement later in the day. The benchmark S&P/TSX Composite Index closed higher on Tuesday, rising 113.94 points or 0.32% to 35,389.58, extending gains for a third straight session on optimism over an initial U.S.-Iran peace deal set to be signed on Friday. Markets are also awaiting more details about the Iran agreement and the signing by Tehran and Washington later this week in Switzerland. In commodities, West Texas Intermediate crude oil futures are up 0.97% at $76.79 a barrel, while gold futures are down 0.27% at $4,342.50 an ounce.