In contrast to the well-known [2 + 2] photocycloadditions between C═O and C═C bonds, the participation of C═N bonds in such reactions is relatively rare. In this paper, the unprecedented UV-light-induced [2 + 2] cycloadditions between N-arylsulfonylimines and styrene derivatives or benzofurans are described. This photolytic reaction allows the highly stereoselective construction of azetidine derivatives
Phase-transfer-catalysed asymmetric synthesis of tetrasubstituted allenes
作者:Takuya Hashimoto、Kazuki Sakata、Fumiko Tamakuni、Mark J. Dutton、Keiji Maruoka
DOI:10.1038/nchem.1567
日期:2013.3
Allenes are molecules based on three carbons connected by two cumulated carbon–carbon double bonds. Given their axially chiral nature and unique reactivity, substituted allenes have a variety of applications in organic chemistry as key synthetic intermediates and directly as part of biologically active compounds. Although the demands for these motivated many endeavours to make axially chiral, substituted
Complementary chemistry! α‐Isocupreine (α‐ICPN) was synthesized for the first time in one step fromquinine by treatment with CF3SO3H (see scheme). This compound serves as an enantiocomplementarycatalyst to β‐isocupreidine (β‐ICD) in the Morita–Baylis–Hillman reaction.
互补化学!通过CF 3 SO 3 H处理,从奎宁一步一步合成了α-异cupreine(α-ICPN)(参见方案)。在Morita-Baylis-Hillman反应中,该化合物可作为β-异cupreidine(β-ICD)的对映体互补催化剂。
Molecular sieve mediated decarboxylative Mannich and aldol reactions of β-ketoacids
作者:Fangrui Zhong、Chunhui Jiang、Weijun Yao、Li-Wen Xu、Yixin Lu
DOI:10.1016/j.tetlet.2013.06.030
日期:2013.8
A molecular sieve mediated decarboxylativeMannichreaction of β-ketoacids with sulfonyl imines is reported; this protocol leads to an efficient preparation of synthetically useful β-amino ketones. An analogous molecular sieve promoted decarboxylative aldol reaction between β-ketoacids and isatins is also described, which affords bioactive 3-substituted-3-hydroxy-oxindoles in excellent yields.
Mix and go: The quinidine amide 1 catalyzed [2+2] cycloaddition between N‐sulfonylimines 2 and alkyl 2,3‐butadienoates 3 afforded the R‐configured azetidines 4 in excellent yields and enantioselectivities (M.S.=molecular sieve). The S enantiomer was obtained when a quinine amide catalyst, the pseudoenantiomer of 1, was used.