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Diastereoselective Synthesis of Spirocyclic Dihydrofurans and 1‐Oxaspiro[4.5]decan‐6‐one Derivatives from Norbornyl α‐Diketones
Author(s) -
Mahadevegowda Surendra H.,
Khan Faiz Ahmed
Publication year - 2015
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201403087
Subject(s) - 2 norbornyl cation , chemistry , tetrahydrofuran , cycloisomerization , organic chemistry , medicinal chemistry , catalysis , solvent
A diastereoselective zinc‐mediated propargylation of non‐enolizable norbornyl α‐diketones and an efficient Ag I ‐catalyzed cycloisomerization of the resulting α‐keto homopropargyl alcohols with terminal alkynes leading to spirocyclic dihydrofurans have been reported. The dihydrofurans obtained were subjected to hydrogenation to afford spiro tetrahydrofuran derivatives in nearly quantitative yields (98–99 %). Eventually, the prepared α‐spiro tetrahydrofuran norbornyl monoketones were utilized as precursors for acid‐mediated Grob‐type fragmentation reactions and converted into 1‐oxaspiro[4.5]decan‐6‐one derivatives by treatment with p ‐toluenesulfonic acid.