Stereoselective synthesis of methyl (1R) - and (1R) -hemicaronaldehydes from natural tartaric acid: Application to the synthesis of s-bioallethrin and deltamethrin insecticides§

A Cross‐Metathesis–Conjugate Addition Route to Enantiopure γ‐Butyrolactams and γ‐Lactones from a C2‐Symmetric Precursor

“…The residue was purified by column chromatography on silica to give 3b (963 mg, 70 %), 3c (298 mg, 17 %), and 3d (129 mg, 5 %). Analytical data of 3b [8] and 3c [53] match those reported in the literature. Analytical data for (2E,2ЈE)-Dimethyl-3,3Ј-{(4R,4ЈR,5R,5ЈR)- …”

Stereodivergent Syntheses of Highly Substituted Enantiopure 4‐Alkoxy‐3,6‐dihydro‐2H‐1,2‐oxazines by Addition of Lithiated Alkoxyallenes to Carbohydrate‐Derived Aldonitrones

“…Finally, we prepared the C 2 -symmetric bis-nitrone 8 and studied its bidirectional reactions [17] with lithiated methoxyallene. Precursor 25 was prepared from d-mannitol as described, [18] and oxidative diol cleavage efficiently provided the dialdehyde 26, which was directly condensed with Nmethylhydroxylamine hydrochloride (Scheme 10). This straightforward two-step procedure afforded a 75 % overall yield of the desired bis-nitrone 8, which was easily purified by recrystallization and may be regarded as a derivative of d-tartaric acid.…”

“…The starting materials nitrones ( [18] methoxyallene [26] and propoxyallene [27] were prepared by literature procedures. All other chemicals are commercially available and were used without further purification.…”

New chiral monodentate phospholane ligands by highly stereoselective hydrophosphination

“…1 H, 13 C, and 31 P NMR spectra were recorded at the following frequencies: 250. For the synthesis of 8 we followed the method described by Krief et al,14 except that the product was used in the next step without further purification.…”