Flash vacuum pyrolysis of steroid propargyl ethers

Owing to its unique rearrangement and cyclization processes via flash vacuum pyrolysis (FVP), the acetylenic moiety has attracted considerable attention by organic chemists as a key building block in the construction of innovative organic architects. Herein, a series of seven steroid propargyl ether precursors have been successfully synthesized and pyrolyzed. Analysis and characterization of the FVP products revealed that the propargyl ethers of phenolic steroids undergo Claisen-rearrangement to give 2-indanone and benzo cyclobutene derivatives, while propargyl ethers of non-aromatic steroids resulted in the corresponding α, β-unsaturated ketones. [Display omitted] •Rearrangement and cyclization of the acetylenic moiety in FVP provides direct access to prepare interesting fused steroids.•Aromatic steroid ethers undergo Claisen-rearrangement to give 2-indanone, benzofuran and 2H-chromene derivatives.•Non-aromatic steroid ethers undergo elemination and thermal isomerization reactions to afford α, β-unsaturated ketones.