The asymmetricKinugasareaction was performed on pure water for the first time without the need for any organic co‐solvents. In contrast to most asymmetricKinugasareactions, trans‐β‐lactams were obtained as the major products in good yields, enantioselectivities, and diastereoselectivities (up to 90 % yield, 98 % ee, and >99:1 d.r.). This reaction is atom‐economical, environmentally friendly, and