Stereospecific Synthesis of Cyclic Hydrazoacetic Acids and meso-Diaminodicarboxylic Acids.

Enantiomerically Pure α-Amino Acid Synthesis via Hydroboration−Suzuki Cross-Coupling

“…mp > 300 °C (dec); 1 H NMR (270 MHz, D 2 O) δ 1.45−1.60 (m, 1H), 1.60−1.75 (m, 1H), 1.88−2.12 (m, 4H), 4.02 (t, J = 5.8 Hz, 2H); 13 C NMR (67.9 MHz, D 2 O) δ 20.9, 29.9, 53.5, 172.9. The spectroscopic data were consistent with those reported 22b…”

“…Application to DAP and DAS Synthesis. We then turned our attention to the utility of the novel organoborane reagent 3 for the synthesis of α,α‘-diamino diacids (DADs, Figure ),12b compounds that have attracted considerable recent attention …”

“…The white precipitate was filtered and then recrystallized (H 2 O−EtOH) to give 40 as a white solid (4 mg, 98%). mp > 300 °C (dec), lit 22b. mp > 300 °C (dec); 1 H NMR (270 MHz, D 2 O) δ 1.45−1.60 (m, 1H), 1.60−1.75 (m, 1H), 1.88−2.12 (m, 4H), 4.02 (t, J = 5.8 Hz, 2H); 13 C NMR (67.9 MHz, D 2 O) δ 20.9, 29.9, 53.5, 172.9.…”

Synthesis of Cyclic Hydrazino α-Carboxylic Acids

“…The research groups of Arakawa and Prinzbach investigated the cycloadditions of dienophile 134 with cyclopentadiene and cyclohexadiene. 91,92 These Diels-Alder conversions gave unsaturated bicyclic adducts 135 in good yields. Oxidative cleavage of the double bond and protection of the resulting carboxylic acids with diazomethane (for easier workup) led to cis-configured cyclic hydrazines 136, which were then deprotected with 6 M hydrochloric acid and acetic acid to the free dicarboxylic acids 137.…”

“…Thus, reaction of Arakawa's diazadicarboxylic acids 138 with hydrogen in the presence of platinum(IV) oxide led to the meso-diaminodicarboxylic acids 139 in quantitative yields (Scheme 21). 92 Additional methods for the cleavage of nitrogen-nitrogen bonds of non-protected diazacycloalkanes are known, making this class of compounds valuable precursors for 1,3-diamines. 93,94 Bols et al described the racemic synthesis of 1-azafagomine, a glycosidase inhibitor, based on the hetero-Diels-Alder reaction of diene 140 and 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD, 141) that produces 142 (Scheme 22).…”