Use of the non-aldol aldol process in the synthesis of the C1–C11 fragment of the tedanolides: use of lactol ethers in place of tetrahydrofurans

The use of a lactol methyl ether 23 in place of the simple tetrahydrofuran 11 allows for the high yielding non-aldol aldol process to occur without concomitant tetrahydropyran formation (cf. 13) to give the desired product 24 in good yield.