Table 4.

Ab initio 6-31G** calculations of energies (eV) and coefficients (C_i) of the frontier molecular orbitals for dienes 1–3 and dienophiles 4–6 ^a.

HOMO							LUMO
Compd b	E (eV)	C1	C2	C3	C4	ΔCic	E (eV)	C1	C2	C3	C4	ΔCic)
1d	−8.8051	0.246	0.164	−0.209	−0.326	0.080	2.9065	0.263	−0.245	−0.245	0.258	−0.005
2d	−8.5610	−0.257	−0.199	0.198	0.320	0.063	3.1035	0.274	−0.222	−0.245	0.248	−0.026
3	−8.6408	−0.277	−0.220	0.199	0.324	0.047	2.7244	0.288	−0.232	−0.247	0.258	−0.030
4a	−8.9382	0.122	0.276	0.015	−0.114	−0.154	1.0104	0.296	−0.210	−0.131	0.113	0.086
4b	−8.4299	−0.084	−0.260	−0.020	0.105	−0.176	1.2204	0.306	−0.203	−0.134	0.112	0.103
4c	−9.0541	0.116	0.265	0.014	−0.109	−0.149	0.7532	0.288	−0.211	−0.126	0.110	0.077
4d	−9.7679	0.160	0.284	0.008	−0.121	−0.124	−0.1056	0.219	−0.196	−0.096	0.092	0.023
5a	−9.2234	0.126	0.275	−0.058		−0.149	0.5331	0.305	−0.227	−0.071		0.078
5b	−8.6859	−0.087	−0.261	0.044		−0.174	0.7611	0.315	−0.219	−0.073		0.096
5c	−9.3227	0.118	0.263	−0.055		−0.145	0.2759	0.298	−0.227	−0.068		0.071
5d	−10.0495	0.163	0.280	−0.073		−0.117	−0.5323	0.238	−0.214	−0.050		0.024
5c	−9.3227	0.118	0.263	−0.055		−0.145	0.2759	0.298	−0.227	−0.068		0.071
6a	−8.6751	0.112	0.257	0.013	−0.100	−0.145	1.7804	0.256	−0.215	−0.153	0.126	0.041
6b	−8.1608	0.043	0.242	0.017	−0.091	−0.199	1.9179	0.272	−0.210	−0.151	0.122	0.062
6c	−8.8008	0.106	0.246	0.012	−0.094	−0.140	1.5032	0.248	−0.215	−0.142	0.119	0.033
6d	−9.5564	0.148	0.271	0.005	−0.108	−0.123	0.5236	−0.164	0.183	0.095	−0.088	−0.019

^aThese are the values of the p_z coefficients, the relative p_z' contributions and their ΔC_i are analogous;

^bThe most stable planar (aryl ring-double bond-numbered trans carbonyl group) s-cis (acrylate moiety) conformation for olefins 4 and 6, and planar (aryl ring-double bond-cyano group) conformation for olefins 5, as shown in the structures at the head of the table;

^cCarbon 4-carbon 1 for the dienes; carbon 1-carbon 2 for the dienophile;

^dReference 17.