A Gold(I)‐Catalyzed Cyclization/Semipinacol Rearrangement Cascade of 1,6‐Enynes to Access Spiro[4.5]decanes and 7‐Azaspiro[4.5]decanes

Abstract

An Au(I)-catalyzed cyclization/semipinacol rearrangement cascade of 1,6-enynes has been developed for the construction of spiro[4.5]decanes and 7-azaspiro[4.5]decanes. The use of JohnPho-sAuCl/NaBARF as a catalyst afforded functionalizable spirocyclic products with good diastereoselectivities of 6.7:1 to > 20:1 dr. A plausible reaction mechanism has also been proposed on the basis of previous literature and our experimental results.

Construction of Spiro[4.5]decanes via Annulations of Azadienes with Nazarov Reagent and DFT Studies

“…As a result, efficient syntheses of such skeleton have attracted continuing interest in the field of organic chemistry. [6] The most common methodologies for the synthesis of spirocyclic compounds relied on the metal-catalyzed [7] or organo-catalyzed domino cyclization reaction. [8] For example, the Lewis acid promoted Nazarov cyclization of α-(trimethyl-silylmethyl)divinyl ketone provided the spiro [4.5]decane skeleton (Scheme 1a).…”