[Pd(PPh₃)₄]‐Catalyzed Diastereoselective Synthesis of trans‐1,2‐Diazetidines from 2,3‐Allenyl Hydrazines and Aryl Halides

Abstract

Strain, what strain? Pd0‐catalyzed cyclization of easily accessed and diversely substituted 2,3‐allenyl hydrazines with aryl halides afforded 1,2‐diazetidines with two chiral centers in high regio‐ and diastereoselectively (trans only; see scheme). Optically active 1,2‐diazetidines were synthesized by using enantiomerically enriched 2,3‐allenyl hydrazines.

Synthesis of sp3-rich chemical libraries based upon 1,2-diazetidines

“…4,10−14 Ma has reported the diastereoselective synthesis of 3,4-disubstituted 1,2-diazetidines via Pd-catalyzed cyclization of chiral 2,3-allenyl hydrazines with aryl halides in good yields. 10 Iacobini et al made 3-methyl 1,2-diazetidines by Rh-catalyzed asymmetric hydrogenation of 3-methylene-1,2-diazetidines. 11a Rajkumar et al have developed a route to 3-vinyl derivatives via Pd-catalyzed asymmetric allylic amination of racemic vinyl epoxide, 14 and most recently, we reported an enantiocontrolled route to 3-aryl 1,2-diazetidines using asymmetric transfer hydrogenation (ATH) as the key step.…”

Regio- and Stereocontrolled Synthesis of 3-Substituted 1,2-Diazetidines by Asymmetric Allylic Amination of Vinyl Epoxide

“…[5][6][7][8] Ma reported the diastereoselective synthesis of 3,4-disubstituted 1,2diazetidines via Pd-catalyzed cyclization of chiral 2,3-allenyl hydrazines with aryl halides in good yields. 5 Alternatively, Iacobini et al made 3-methyl-1,2-diazetidines by Rhcatalyzed asymmetric hydrogenation of 3-methylene-1,2diazetidines. 6 However, neither method is well suited for the synthesis of 2, which crucially requires differentiation of the two nitrogen atoms.…”

Density functional estimation of hydride and proton affinities of substituted allenes and heteroallenes

“…[33][34][35] On the other hand, the chemistry of allenes has been extensively studied, due to their high reactivity than the alkenes. [36][37][38][39][40] Allenes can usually be reduced by a reductant such as H À and one of its double bonds can be broken. The HAs of allenes containing phenyl sulfone A in acetonitrile have been examined, and the results indicated that this type of allenes meet HAs much higher than dienes (Scheme 1).…”