Stereoselective synthesis of constrained norbornane-derived spiro-β-lactams

An efficient synthesis of spiro- β-lactams having sulfenyl, sulfinyl and sulfonyl moiety

“…7 Although a great deal of functionalized monocyclic β-lactams has been reported, relativly few reports have been devoted to the synthesis of spiro-β-lactams. [8][9][10][11] Among the different strategies developed for the construction of β-lactams, 12 the reaction of acid chlorides with imines i.e., Staudinger reaction 13 constitutes one of the most popular procedures. In view of the ever growing applications of spiro-β-lactams, ranging * For correspondence from their biological activity to their utility as synthetic intermediates in organic synthesis, we extended our work on C-3 alkylation of 3-methylthio-β-lactams to the synthesis of spiro-β-lactams.…”

An update on the synthesis and reactivity of spiro-fused β-lactams

“…The ratio of diastereoisomers was determined by integration of the H-4 proton in the 1 H-NMR spectra of the crude reaction mixtures. 45 Scheme 11 To study the synthesis of spiro-β-lactam 46 on a larger scale, the reaction of in situ generated ketene from compound 44 and imine 45 was conducted in both batch and flow mode (Scheme 12). The reaction outcome showed that the Staudinger synthesis in a continuous flow process was deemed a safe method for this highly exothermic reaction.…”

“…The norbornane-derived spiro-β-lactams 40-41b have been subjected to acid hydrolysis (HBr), giving rise to the corresponding norbornane-derived β-amino acids 135 and 136 (Scheme 41). 45…”

Dynamic Kinetic Resolution of Phosphinic Acid Derivatives via Nucleophilic­ Substitution at Phosphorus Center

“…The reaction mixtures were purified by column chromatography over silica gel (60-240 mesh). (R)-Pulegol (5a), 22 exo-borneol (5c), 23 cis-myrtanol (5f), 24 endo-camphanol (5g), 24,25 (-)-isopinocampheol (5h), 24 (R)-1mesitylpropan-2-ol (5j), 26 (S)-2-mesityl-1-phenylethanol (5k), 26,27 methyl methylphenylphosphinate, 12a o-anisylphenylphosphine oxide, 28 o-tolylphenylphosphine oxide, 29 1-naphthylphenylphosphine oxide, 30 benzylphenylphosphine oxide, 31 and tert-butylphenylphosphinic chloride (9e) 32 were prepared according to the literature procedures or were available from other research projects running in our laboratories. The preparation of compounds 7 and 8, and details of the reaction of racemic 3 with chiral alcohols (Table 2) are provided in the Supporting Information.…”

“…NMR (CDCl 3 , 202 MHz): δ (major) = 27.8; δ (minor) = 27.4. MS (EI, 70 eV): m/z (%) = 279 (19), 262 (6), 261 (66), 167 (52), 150 (12), 149 (100), 121(22), 113(22), 112 (83), 104(25), 95(11), 84(40), 83 (54), 82 (14).HRMS (ESI-TOF): m/z [M + H] + calcd for C 23 H 31 O 3 P: 387.2091; found: 387.2084. The data are in accordance with those previously reported in the literature.…”