Schematic models for TS_R(X) and TS_S(X) and summary of hydrogen bonding interactions in the TSs of the Diels–Alder reaction of parent 2a (X = H) with redesigned dienylcarbamates 7a (X = Br) and 8a (X = NO₂).

L: length (Å), A: angle (°)	TSR(H)	TSR(Br)	TSR(NO2)	TSS(H)	TSS(Br)	TSS(NO2)
L (H1–O1)	1.65	1.65	1.64	1.65	1.65	1.64
A (N1–H1–O1)	169	170	170	171	171	171
E (H1–O1)	13.3	13.7	13.9	12.8	12.5	12.8
L (H2–O2)	1.75	1.76	1.76	2.16	2.17	2.14
A (N2–H2–O2)	167	165	165	123	123	124
E (H2–O2)	10.4	9.9	10.0	1.3	1.2	1.4
L (H 3 –O 2 )	2.60	2.37	2.31	—	—	—
A (C1–H3–O2)	167	168	172	—	—	—
E (H 3 –O 2 )	0.8	1.8	2.3	—	—	—
L (H4–O2)	—	—	—	2.19	2.17	2.19
A (C2–H4–O2)	—	—	—	123	124	122
E (H4–O2)	—	—	—	2.4	2.6	2.4
L (H5–C3)	—	—	—	2.82	2.81	2.76