Borrowing Hydrogen/Chiral Enamine Relay Catalysis Enables Diastereo- and Enantioselective β-C-H Functionalization of Alcohols

We report herein an unprecedented borrowing hydrogen/chiral enamine relay catalysis strategy that enables a highly efficient enantioselective formal beta-alkylation of simple alcohols using electron-deficient alkenes and especially nitroalkenes. A variety of 1,4-difunctional products such as nitro alcohols are readily accessible in one waste-free step from feedstock alcohols in excellent levels of stereoselectivity. It is important to note that the products are formed in much higher diastereoselectivity than the enamine catalysis step alone under identical conditions, highlighting the unique advantage of cascade borrowing hydrogen catalysis in achieving high efficiency, economy, and stereoselectivity.