Highly diastereoselective construction of functionalized cyclopenta[d][1,2]oxazines is achieved from 1-aryl propargyl alcohols via sequential oxyamination/annulation reactions.

Longanlactone analogues were synthesized using a route featuring Friedel-Crafts acylation, Sonogashira coupling and 1,3-dipolar cycloaddition reactions. Structure-activity relationships were investigated for neurotrophic activity. Compound 6 was found to have the most potent neurotrophic activity among all the synthesized analogues in Neuro2a cells as evidenced by a battery of in vitro/cell based assays for assessment of neurogenic and potential neurotrophic activity including neurite outgrowth assay and real time PCR for popular markers of augmented neurotrophic activity. Compound 6 might serve as a template for further development of highly effective neurotrophic molecules.

Alkyne-assisted metal-free oxa-[3+3] annulation of MBH-carbonates of propiolaldehydes with α-nitro/bromo ketones to access alkynyl 2H-pyrans is described. The products allowed further annulations to obtain diverse pyrano[3,4-c]pyran-1-ones.