A concise process for the stereoselective synthesis of chiral cis-3-alkoxy-2-carbomethoxy medium-ring oxacycles from (R)-3-(3-butenyl)-4-propynoyloxazolidin-2-one (1) was developed. The process includes five major steps: (i) hetero-Michael reaction between an alcohol and 1, (ii) stereoselective reduction of the resulting ketone, featuring stereochemical assistance of the neighboring oxazolidin-2-one