with similar selectivity (entry 2). The reaction conditions were reoptimized using vinyliodonium salts with varying counter ions, and enhanced yields and diastereoselectivities were observed with both 4a(BF4) and 4a(OTs) (entries 3, 4). While reactions in acetone performed poorly (entries 5, 6), the transformation benefitted from lower temperature, and reactions at -15 °C gave significantly increased yield of 5a (entries 7, 8). Further improvements were observed with 2c upon initially lowering the temperature to -40 °C followed by reaction at rt, which gave 5a in 92% yield with excellent E:Z selectivity (entry 9). Increased reaction scale delivered 5a in high isolated yield and excellent E:Z selectivity using both 4a(BF4) and 4a(OTs) (entries 10, 11).