Preparation of sterically crowded t-butylfurans by direct t-butylation and cyclisation of t-butyl substituted 1,4-diketones. Selective dehydrodimerisation of neopentyl ketones by lead dioxide

o-Di-t-butylfurans can be obtained in high yields via Friedel–Crafts alkylation and via cyclisation of 1,4-diketones, but minor differences in the substitution pattern of the starting materials prevent o-di-t-butylation, or govern escape reactions to relieve the steric strain.