Nitrile Oxides, Nitrones, and Nitronates in Organic Synthesis : Novel ...

666 NITRONATES
Table 3.29 The study of stereodynamic of substituted 3-alkylen-4H -tetrahydro-1,2-oxazines with dynamic NMR (Scheme 3.228)
Ratio of ΔG # 298, ΔH # , ΔS # ,
Product Si R2a R4 R5 Process conformers kJ/mol kJ/mol J/mol*K
−22.3 ± 9.7
−14.3 ± 9.8
−37.3 ± 7.7
−35.8 ± 9.1
−31.3 ± 10.7
−32.0 ± 13.3
−35.7 ± 9.0
−37.1 ± 8.5
−59.0 ± 10.0
−40.6 ± 9.9
−27.3 ± 9.1
−19.8 ± 9.8
−15.1 ± 10.0
2.5 ± 9.7
−76.4 ± 9.0
−77.7 ± 9.9
60.8 ± 8.5
39.8 ± 10.2
74.4 ± 6.2
−39.0 ± 6.0
53.2 ± 2.7
52.4 ± 2.7
48.4 ± 2.0
45.7 ± 2.4
50.2 ± 2.6
45.9 ± 3.3
49.4 ± 2.5
47.6 ± 2.4
45.0 ± 2.7
46.0 ± 2.6
50.5 ± 2.5
52.4 ± 2.6
56.2 ± 2.8
60.6 ± 2.7
36.7 ± 3.0
31.7 ± 2.3
83.1 ± 2.7
77.5 ± 3.2
44.7 ± 1.9
53.9 ± 1.9
430a TMS Ph Me Me IN A/B 4:1 A→B: 59.8 ± 2.9
B→A: 56.7 ± 2.9
430b TBS Ph Me Me IN A/B 4:1 A→B: 59.5 ± 2.3
B→A: 56.4 ± 2.7
430c TMS An OMe Me IN A/B 9:1 A→B: 59.5 ± 3.1
B→A: 55.4 ± 3.9
430d TMS An H OEt IN A/B 3:1 A→B: 60.1 ± 2.7
B→A: 58.7 ± 2.5
430e TMS An OEt H IR or IN +IR A/(C or D) =4:1 A→C: 61.7 ± 2.8
C→A: 58.1 ± 3.5
430f TBS OBz Me Me IR or IN +IR (C or D)/A 1.1:1 C→A: 58.7 ± 2.7
A→C: 58.4 ± 2.9
430g TMS OBz Me Me IR or IN +IR A/(C or D) 3:2 A→C: 60.7 ± 3.0
C→A: 59.8 ± 2.9
430h TMS OBz OMe Me IR or IN +IR A/(C or D) 9:1 A→C: 59.5 ± 3.8
C→A: 54.9 ± 2.9
430i TMS An Ph H IN (C or D)/twist 3:2 C→tw: 65.6 ± 2.6
tw→C: 65.0 ± 3
430j TMS An H Ph IN A:B=3:2 A→B: 66.9 ± 1.8
B→A: 65.6 ± 1.8
a R 1 =R 3 =H; TMS–SiMe3; TBS–SiMe2Bu t ; An–4-MeO-C6H4.