Nickel-Catalyzed Asymmetric Addition of Aromatic Halides to Ketones: Highly Enantioselective Synthesis of Chiral 2,3-Dihydrobenzofurans Containing a Tertiary Alcohol
A highlyenantioselective and straightforward synthetic procedure to chiral 3-hydroxy-2,3-dihydrobenzofurans has been developed by nickel/bisoxazoline-catalyzed intramolecular asymmetric addition of aryl halides to unactivated ketones, giving 2,3-dihydrobenzofurans with a chiral tertiary alcohol at the C-3 position in good yields and excellent enantioselectivities (up to 92% yield and 98% ee). The
Copper-catalyzed double C–S bond formation for the synthesis of 2-acyldihydrobenzo[<i>b</i>]thiophenes and 2-acylbenzo[<i>b</i>]thiophenes
作者:Subramani Sangeetha、Govindasamy Sekar
DOI:10.1039/d0cc04647g
日期:——
An efficient domino process is developed for the synthesis of diversely substituted 2,3-dihydrobenzo[b]thiophenes from 2-iodoketones using a Cu-catalyst and easily available xanthate as a sulfur surrogate in good yields. This domino method has been expanded for the synthesis of 2-acylbenzo[b]thiophenes using in situ generated iodine (I2) from by-product KI in high yields. Treatment of xanthate with
开发了一种有效的多米诺方法,该方法使用铜催化剂和易于获得的黄原酸酯作为硫代用品,以高收率从2-碘酮合成各种取代的2,3-二氢苯并[ b ]噻吩。该多米诺法已得到扩展,可利用副产物KI的原位生成的碘(I 2)高产率地合成2-酰基苯并[ b ]噻吩。用铜(II)催化剂处理黄药可能将其还原为铜(I)催化剂,从而启动催化循环。根据XPS分析,碘色测试和其他几个对照实验的结果,提出了一种可能的机制。
Palladium-catalyzed carbonylative cyclization via trapping of acylpalladium derivatives with internal enolates. Its scope and factors affecting the C-to-O ratio
作者:El-ichi Negishi、Christophe Copéret、Takumichi Sugihara、Izumi Shimoyama、Yantao Zhang、Guangzhong Wu、James M. Tour
DOI:10.1016/s0040-4020(01)80765-1
日期:1994.1
The Pd-catalyzed carbonylative cyclization reaction involving omega-acyl-substituted acylpalladium derivatives can proceed via intramolecular trapping with either C- or O-enolates; the preferential formation of either 5- or 6-membered rings dictates the C-to-O ratio in the trapping with enolates.
Catalytic generation and trapping of acylmetals containing Ni and Cu with enolates
Carbonylative cyclization of iodoarenes and iodoalkenes containing a proximal enolate precursor can selectively provide either cyclic ketones or lactones in the presence of Ni or Cu catalysts via trapping of putative acylmetal derivatives with C-or O-enolates, respectively; the ring size and regioselectivity of the reaction may be predicted based on two generalizations derived from the recently developed corresponding Pd-catalyzed reaction. (C) 1998 Elsevier Science Ltd. All rights reserved.