Copper-Catalyzed\nCarbomagnesiation of 1‑Halocyclopropenes

We report a versatile copper-catalyzed carbomagnesiation\nreaction\nof poly- and fully substituted 1-halocyclopropenyl esters. By fine-tuning\nthe regioselectivity of the addition, we were able to access configurationally\nstable fully substituted cyclopropyl carbenoid intermediates. These\nintermediates were subsequently trapped with electrophiles to furnish\nstereodefined poly- and fully substituted halocyclopropyl esters.\nThe regioselectivity of the addition was found to be dependent on\nthe nature of the sp<sup>2</sup> substituents.