Highly Regio- and Stereoselective Intramolecular Rearrangement of Glycidol Acetal to Alkoxy Cyclic Acetals.

Meera Johny, Rose Mary Philip, Goreti Rajendar

Organic letters 2022 Aug 26

filter terms:

A new class of highly regio- and stereoselective intramolecular rearrangements of glycidol acetals to produce alkoxylated 1,3-dioxolane/1,3-dioxane is demonstrated. Selective Lewis acid activation of acetal generates an oxocarbenium ion that initiates the epoxide ring-opening event, giving the bicyclic [3,1,0]epoxonium ion intermediate that undergoes exo/endo-selective opening by a tethered alkoxide. Mechanistic insights into preferential acetal activation over the epoxide were obtained by crossover experiments. The method was applied in the total synthesis of parvistone B and its 8-ethoxy analogue.

Citation

Meera Johny, Rose Mary Philip, Goreti Rajendar. Highly Regio- and Stereoselective Intramolecular Rearrangement of Glycidol Acetal to Alkoxy Cyclic Acetals. Organic letters. 2022 Aug 26;24(33):6165-6170