A stereoselective approach for the southeast segment (C1-C16) of (+)-sorangicin A.

The stereoselective protective group-free synthesis of the C1-C16 fragment of (+)-sorangicin A consisting of a dihydropyran subunit with a chiral alkyl substituent is achieved. The synthesis of the 4-stereogenic centered subunit involved key reactions such as Noyori asymmetric transfer hydrogenation, Achmatowicz oxidative rearrangement, and highly diastereoselective allylation of the Achmatowicz adduct.