alpha-Iodoalkyl ylides were prepared and used for first time to convert aldehydes to 2-iodo-2-alkenes stereoselectively and to other dialkyl vinyl iodides.
Terminal allenes react smoothly with B-iodo-9-borabicyclo[3.3.1]nonane (B-iodo-9-BBN), and the subsequent protonolysis with acetic acid gives the corresponding 2-iodoalkenes.