On the reaction of diphenylketene with isocyanides

Abstract

The products obtained from the reaction of diphenylketene with a variety of isocyanides are shown to depend heavily on the concentration of diphenylketene; a high concentration results in the precedented dioxolane derivatives, at much lower concentrations the reactions follow an alternative course and polycyclic beta-lactams are generated by a cascade of formal pericyclic reactions.

Diversity oriented and chemoenzymatic synthesis of densely functionalized pyrrolidines through a highly diastereoselective Ugi multicomponent reaction

“…In this case the overall yield (8 steps from 6) was 64%. In order to explore the possibility to obtain 2 or its enantiomer by a shorter sequence, we also tried to transform both 6 and 20 into bisformamides 25 (R = Ac or Ar), by treatment with sodium diformylimide of the corresponding mesylates, 24 having in mind to selectively hydrolyze one formyl group. While the nucleophilic substitution gave about 62% overall yield in both performing one in the acetylation of 31 using vinyl acetate as solvent (e.e.…”

“…A solution of (R)-or (S)-19 (123 mg, 306 mmol) in dry CH 2 Cl 2 (2.5 mL) was cooled to -30 (8.5), 326 (43), 301 (6.5), 299 (6.7), 271 (12), 269 (11), 259 (11), 257 (10), 233 (5.0), 232 (14), 231 (100), 230 (15), 229 (96), 220 (7.7), 187 (23), 185 (24), 180 (6.0), 179 (5.5), 157 (14), 155 (14), 151 (5.1), 150 (9.4), 149 (7.9), 146 (6.5), 139 (9.7), 137 (9.6), 135 (12), 131 (6.0), 127 (9.9), 115 (13), 114 (24), 99 (9.4), 89 (6.7), 86 (5.0), 85 (11), 84 (39), 78 (5.4), 77 (7.3), 76 (20), 75 (34), 74 (6.0), 73 (46), 71 (11), 64 (5.2), 63 (6.7), 59 (25), 58 (10), 57 (12), 55 (5.7), 53 (5.1), 47 (6.6), 45 (12), 43 (14), 41 (37), 39 (10). m/z (ESI+) 406.0795 (M + Na + ).…”

“…Compound 21 was transformed into the corresponding primary amine following the procedure reported for compound (10), 172 (11), 155 (7.4), 154 (34), 153 (16), 110 (12), 109 (100), 108 (32), 98 (9.0), 96 (17), 95 (24), 93 (20), 84 (6.2), 82 (5.6), 81 (46), 79 (13), 77 (7.7), 76 (5.0), 69 (7.6), 68 (5.0), 67 (42), 65 (6.9), 59 (13), 58 (45), 56 (5.7), 55 (25), 53 (10), 46 (8.3), 43 (15), 41 (31), 39 (12). m/z (ESI+) 348.0576 (M + Na + ).…”

An unusual methylene aziridine refined inP21/cand the nonstandard settingP21/n

“…The title compound, 6-tert-butyl-3-oxa-2-thia-1-azabicyclo-[5.1.0]oct-6-ene 2,2-dioxide, (1), and related methylene aziridines (Feast et al 2009) were prepared during our ongoing study of nitrogen-containing 1,3-dipoles (Robertson et al, 2005;White, 2007) in order to probe their potential as 2-aminoallyl cation precursors (Prié et al, 2004).…”

Synthesis and reactivity of spiro-fused β-lactams

“…18 In one case, theoretical calculations indicated torquoelectronic effects dominating, but the experimental findings suggested steric and other electronic factors determining the course of the reactions. 23 The experimental findings of Deshmukh and coworkers showed that the torquoelectronic effects dominated the steric constraints.…”