Reactivity Switch in Glycal Dienes toward Different Nucleophiles: Mechanistic Insight and Applications toward the Synthesis of Naphthalene-Fused Pyran Derivatives.

The stereo- and regioselective formation of chiral molecules is an interesting and important topic in organic synthesis due to its wide applicability and intricacy during synthesis. Herein, we disclose a method for the selective functionalization of glycal dienes for synthesizing different glycosides and branched sugars stereo- and regioselectively. The methodology is broad regarding the substrate scope in which various nucleophiles and glycals were explored. Furthermore, we delve into converting the synthesized products into naphthalene-fused pyran derivatives, achieved through a 4 + 2 cycloaddition followed by aromatization. Additionally, we conducted density functional theory studies to gain insight into the formation of regioselective products when different nucleophiles were employed.