Evaluation of (+)‐Sparteine‐Like Diamines for Asymmetric Synthesis.

Abstract

Evaluation of (+)-Sparteine-Like Diamines for Asymmetric Synthesis. -The known (+)-sparteine surrogate (Ia) and three new analogues (Ib)-(Id) are tested in two different reactions, the α-lithiation rearrangement of cyclooctene oxide and the oxidative kinetic resolution of 1-indanol. Diamines (I) exhibit enantioselectivity opposite to that observed with (-)-sparteine. From the present and previously reported results it is concluded that diamine (Ia) is the most useful (+)-sparteine surrogate today. It is applied with much success in four other reactions, but fails in the attempted dynamic resolution of lithiated borane (XVI). -(DEARDEN, M. J.; MCGRATH, M. J.; O'BRIEN*, P.; J.

Semisynthesis of novel N‐acyl/sulfonyl derivatives of 5(3,5)‐(di)halogenocytisines/cytisine and their pesticidal activities against Mythimna separata Walker, Tetranychus cinnabarinus Boisduval, and Sitobion avenae Fabricius

“…Yield: 34%, white solid, m.p. 203–205 °C [literature, 203–205 °C]; [α] 25 D = −46 ( c 2.1 mg mL −1 , CHCl 3 ); IR cm −1 (KBr): 2932, 2830, 1645, 1548, 1456, 1366, 1063, 807; 1 H NMR (500 MHz, CDCl 3 ) δ : 7.35 (dd, J = 13.0 Hz, 7.0 Hz, 1H, H‐4), 6.57–6.61 (m, 1H, H‐3), 6.18 (d, J = 6.0 Hz, 0.53H, H‐5), 6.13 (d, J = 6.0 Hz, 0.45H, H‐5), 4.81 (d, J = 13.0 Hz, 0.47H), 4.69 (d, J = 13.0 Hz, 0.55H), 4.18 (d, J = 16.0 Hz, 0.55H), 4.12 (d, J = 15.5 Hz, 0.47H), 3.84–3.95 (m, 2H), 3.43 (t, J = 14.0 Hz, 1H), 3.12 (br, s, 1H, H‐7), 2.87 (d, J = 13.0 Hz, 0.53H), 2.82 (d, J = 13.5 Hz, 0.47H), 2.56 (d, J = 15.0 Hz, 1H, H‐9), 2.01–2.08 (m, 3.52H, H‐8, COCH 3 ), 1.74 (s, 1.41H, COCH 3 ); HRMS (ESI): Calcd for C 13 H 17 N 2 O 2 ([M+H] + ), 233.1284; Found, 233.1283.…”

Shaping Molecular Landscapes: Recent Advances, Opportunities, and Challenges in Dearomatization

“…22 Bis-m-oxodicopper-sparteine complex 32 (formed in situ from a copper salt, the alkaloid, and molecular oxygen) was shown to be a competent tyrosinase mimic, capable of promoting the asymmetric oxidative dearomatization of 2-methylresorcinols such as 33 (Figure 3). Given that the (+)-sparteine enantiomer is not readily available, Porco and co-workers extended their asymmetric method by using the accessible (+)-sparteine surrogates reported by O'Brian, 23 rendering the asymmetric oxidative dearomatization stereodivergent. 24 The group has also reported several protocols for constructing the pyranoquinone nucleus of the azaphilone core 34-through cycloisomerization of the oalkynylbenzaldehyde moiety-under carefully buffered conditions 24 via gold(III) or copper(I) catalysis.…”