Preparation of trans-1-propenyl-magnesium bromide solution (This procedure can also be used for preparation of cis-1-propenyl-magnesium bromide solution): A 500 mL two-neck oven dried round-bottom flask was charged with a stir bar, Mg turnings (2.88 g, 118 mmol, 1.2 equiv.), I2 (0.254 g, 1 mmol, 0.01 equiv.), and THF (200 mL). A reflux condenser was attached to one neck of the flask. Trans-1-bromo-1propene (8.5 mL, 12.0 g, 99 mmol, 1 equiv.) was added to the flask dropwise at room temperature, and the heterogeneous mixture was heated to 60 °C for 3 hours using an oil bath. Following this time, the reaction was cooled to room temperature and stirred for an additional 12 hours. Note: The following reaction was performed in two separate batches of 6 g each. The yield is reported for both batches combined.