Diastereoselective Synthesis of Spirocyclic Dihydrofurans and 1‐Oxaspiro[4.5]decan‐6‐one Derivatives from Norbornyl α‐Diketones. Issue 4 (18th December 2014)

• Record Type: Journal Article
• Authors: Mahadevegowda, Surendra H.; Khan, Faiz Ahmed
• Is Part Of: European journal of organic chemistry. Issue 4(2015)
• Page Start: 858
• Page End: 870
• Publication Date: 2014-12-18
• Subjects: Synthetic methods -- Diastereo­selectivity -- Oxygen heterocycles -- Spiro compounds -- Ketones; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.201403087
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract: 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. Abstract : A diastereoselective propargylation of non‐enolizable norbornyl α‐diketones and an efficient Ag I ‐catalyzed cycloisomerization of the resulting α‐keto homopropargyl alcohols bearing terminal alkynes leading to spirocyclic dihydrofurans have been reported. This methodology has been successfully used to synthesize 1‐oxaspiro[4.5]decan‐6‐ones through acid‐mediated Grob‐type fragmentation reactions.