Compound 3a
6,10-Dimesityl-2,8,8-trimethyl-1-oxa-6,10-diazaspiro[4.5]dec-2-ene-7,9-dione
From: Diamidocarbenes as versatile and reversible [2 + 1] cycloaddition reagents
From: Diamidocarbenes as versatile and reversible [2 + 1] cycloaddition reagents