. Author manuscript; available in PMC: 2011 Mar 17.

Published in final edited form as: J Am Chem Soc. 2010 Mar 17;132(10):3304–3311. doi: 10.1021/ja903653j

Table 5.

Approximate decomposition of computed electronic energy barrier differences (ΔΔE^‡) into π-stacking (ΔΔE_stack, see Fig. 4) and substituent effects on the underlying Diels-Alder barriers (ΔΔE_sub) for the reactions in Scheme 1. The dominant contribution arises from ΔΔE_π.

Substrate		ΔΔE^‡	ΔΔE_stack	ΔΔE_sub
Me	1b	0.0	0.4	0.1
OMe	1c	2.6	1.3	1.0
Br	1d	3.5	2.9	0.9
Cl	1e	3.3	2.5	0.8
F	1f	2.6	1.6	0.3

Substrate		ΔΔE^‡	ΔΔE_stack	ΔΔE_sub
Me	1b	0.0	0.4	0.1
OMe	1c	2.6	1.3	1.0
Br	1d	3.5	2.9	0.9
Cl	1e	3.3	2.5	0.8
F	1f	2.6	1.6	0.3

Substrate		ΔΔE^‡	ΔΔE_stack	ΔΔE_sub
Me	1b	0.0	0.4	0.1
OMe	1c	2.6	1.3	1.0
Br	1d	3.5	2.9	0.9
Cl	1e	3.3	2.5	0.8
F	1f	2.6	1.6	0.3

Substrate		ΔΔE^‡	ΔΔE_stack	ΔΔE_sub
Me	1b	0.0	0.4	0.1
OMe	1c	2.6	1.3	1.0
Br	1d	3.5	2.9	0.9
Cl	1e	3.3	2.5	0.8
F	1f	2.6	1.6	0.3