Scheme 1. The newly proposed mechanism for the C–C bond formation at the synergistical BAS/LAS sites over zeolite catalysts. (Ads, represents the adsorbed DME; A, represents Al–OH-bound methyl (Al–OHCH₃); A′, represents the Al-bound methoxide (Al–OCH₃); B, represents the Al–OCH₂⁺ intermediate; C, represents the Al-bound ethoxide (Al–O–CH₂CH₃); TS, represents the transition state).