Nucleophilic Addition of Potassium O-Ethyl Dithiocarbonate to Baylis-Hillman Adducts Using 9-BBN as Catalyst

an efficient diastereoselective michael addition of the commercial potassium o-ethyl dithiocarbonate to baylis-hillman adducts in the presence of 9-bbn (9-borabicyclo[3.3.1]nonane) as a lewis acid is reported. 9-bbn both protected the hydroxyl group and activated the carbonyl of the michael acceptor.