Synthesis of the C17–C25 subunit of lasonolide A utilizing a Tsuchihashi–Yamamoto type rearrangement

An efficient synthesis of the C17–C25 subunit resident in (−)-lasonolide A is reported herein. The key reaction features that were utilized include a Tsuchihashi–Yamamoto type rearrangement and Molander–Reformatsky SmI2 mediated intramolecular aldol reaction sequence. Lastly, a diastereoselective target oriented β-C-glycoside formation sequence via an oxocarbenium reduction completed the stereochemistry required for the completion of the C17–C25 segment of (−)-lasonolide A.