Synthesen in der hydroaromatischen Reihe. II. Die Diensynthese von Derivaten des 1‐Äthinyl‐3,4‐dihydro‐naphtalins und des 1‐Vinyl‐3,4‐dihydro‐naphtalins

Chemical consequences of fluorine substitution. Part 4. Diels–Alder reactions of fluorinated p-benzoquinones with Dane's diene. Synthesis of fluorinated D-homosteroids

“…Dane's diene 24 (1) was synthesised according to the literature procedure. 25 In our hands, the Grignard reaction of vinylmagnesium bromide with 6-methoxy-α-tetralone ‡ always yielded mixtures of the expected allylic alcohol 1,2,3,4-tetrahydro-6methoxy-1-vinyl-1-naphthol (4) and Dane's diene (1) in ratios varying from 4 : 1 to 1 : 2 (4 : 1, 1 H NMR).…”

“…Spectroscopic data were obtained from the spectra of the two regioisomeric mixtures. 13 C NMR (acetone-d 6 ) δ 26.5 (t, C-5 or C-6), 27.2 (t, C-5 or C-6), 31.2 (t, C-12), 38.1 (dd, 4 J C,F 2.6, C-4b), 48.6 (d, C-12a), 50.0 (dd, 3 J C,F 3.8, C-4a), 54.9 (q, OCH 3 ), 113.1 (d, C-7 or C-9), 113.4 (d, C-7 or C-9), 114.6 (d, C-11), 117.2 (dd, 3 J C,F 8.9, C-2), 124.9 (d, C-10), 127.2 (s, C-10a), 129.4 (s, C-10b), 138.5 (s, C-6a), 159.2 (s, C-8), 191.9 (d, 3 J C,F 14.5, C-1), 198.8 (d, 2 J C,F 21.1, C-4); 54 19 F NMR (acetone-d 6 ) δ Ϫ111.7 (d, 3 J F,H 12.2); m/z 312 (100%, M ϩ ), 297 (12, M ϩ Ϫ CH 3 ), 295 (14), 291 (12), 290 (13), 284 (36, 312 Ϫ CO), 281 (9, M ϩ Ϫ OCH 3 ), 249 (14), 207 (14), 191 (24), 167 (24), 147 (32), 115 (13). 55 Compound 7b.…”

“…55 Compound 7b. 1 H NMR (acetone-d 6 ) δ 1.78-1.88 (m, 1 H, 5-H), 2.27 (ddt, 3 or 2 J H,H 12.9, 12.2); m/z 312 (100%, M ϩ ), 297 (26, M ϩ Ϫ CH 3 ), 295 (23), 291 (13), 284 (4, 312 Ϫ CO), 263 (36), 249 (23), 220 (24), 207 (23), 167 (28), 109 (22), 88 (27). 55 3-and 2-Fluoro-8-methoxy-4a,5,6,11,12,12a-hexahydrochrysene-1,4-dione (8a and 8b).…”

A Cascade Suzuki–Miyaura/Diels–Alder Protocol: Exploring the Bifunctional Utility of Vinyl Bpin

“…Employing conditions previously established in our group, [21][22][23][24][25] the Suzuki-Miyaura event proceeded rapidly and quantitatively, delivering Dane's diene (2a) as an intermediate. 26,27 We believed thermal promotion would enable cyclization, and a temperature screen indicated that a minimum of 150 °C (Table 1, entries 1-4) was necessary to drive the DA reaction to completion; 5 equivalents of vinyl BPin were required to overcome organoboron degradation and offset a competing homo DA consuming diene intermediate 2a (Table 1, entries 6-8). A time study indicated that the reaction was complete in 6 h (Table 1, entries 9 and 10).…”

Ab + D → Abcd

“…The diene 1 has been condensed with numerous other dienophiles [15][16][17][18][19][20][21][22][23][24][25]29], as has 16 [26][27][28]30]. A wide variety of dienes has been utilized, many of them by a Russian group associated with I. N. Nazarov.…”