“…Recently, the catalytic synthesis of optically active cyclohexa-1,3-dienes from β-branched α,β-alkenals and various monoalkyl ylidenemalonates was described, 1 and factors affecting the apparent (net) enantioselectivity of this process were studied. 2 The reaction mechanism (Scheme 1) 1-3 involves the transient formation of a dienamine followed by two consecutive, inherently diastereoselective reactions. One of them, intermolecular [4+2] cycloaddition, is strongly accelerated by pressure, 4 whereas the other is believed to proceed via a six-membered transition state, 5 which can also be affected by pressure.…”