Diastereoselective Intramolecular Aldol‐Type Trapping of Zwitterionic Intermediates by Ketones for the Synthesis of Spiro[chroman‐4,3′‐oxindole] Derivatives

Abstract

As imple,m ild and efficientr hodium-catalyzed aromaticC -H functionalization of a-phenoxy ketones by 3-diazooxindolesf or the synthesis of the spiro[chroman-4,3'-oxindole] ring system is described. As eries of functionalized spiro[chroman-4,3'-oxindole] derivatives bearing twoa djacent quaternary carbon centers have been attained in ah ighly diastereoselectivem anner with very good yields.Control experiments suggested the possibility of an intramolecular aldol-type trapping of zwitterionic intermediates aftert he C-H functionalization. Furthermore,t he applicability of this method has been tested by ag ram-scale synthesis. Af acile treatment with base enabled the access to both synand anti-diastereomers via isomerization.

Stereoselective synthesis and applications of spirocyclic oxindoles

“…407 In other approaches, Subba Reddy has developed a BF 3 •OEt 2 mediated Prins cascade cyclisation between aldehydes and butanamides to furnish spiroTHP oxindoles in high yield and good dr. 408 Hu used Rh-carbenes generated from 3-diazooxindoles to undergo C-H insertion/aldol condensation to afford spiroTHP oxindoles in high yield and diastereoselectivity. 409 Another example of C-H activation has been shown by Messaoudi with glycosides. 410 The intramolecular Co-catalysed Pauson-Khand cyclisation of 1,7-enynes generated 3,2′-spiroTHPs with high diastereoselectivity.…”

Rhodium‐Catalyzed [5+1]‐Cycloaddition Reactions to Spiro‐Benzo[e][1,3]Oxazineindoline Imines

“…The substituted indoline‐2,3‐diones (Isatin) or 3‐iminoindolin‐2‐ones as indolyl sources to give 3‐spiro[3‐azabicyclo[3.1.0]hexane]‐oxindoles were found to be achieved in regio‐ and enantiocontrolled protocols. Recently, Hu reported a Rh‐catalyzed the [5+1]‐cycloaddition reaction of 3‐diazooxindoles, which derived from Isatin analogues, with α‐phenoxy ketones to produce functionalized spiro[chroman‐4,3′‐oxindoles] (Scheme , eq 1) . In 2014, Wang and co‐workers firstly reported the preparation of a new dizao derivative of indoline‐2,3‐dione, 3‐diazoindolin‐2‐imine, and used this compound as precursor of metal carbenes for a variety of important transformations, such as formal cycloadditions, C−N coupling and N−H/C−H insertion reactions .…”

Development of Transition-Metal-Catalyzed C(sp2)-H Functionalization of Arenes with Diazo Compounds

“…当使用手性膦配体时也可以实现不对称催化, 但是结果 不够理想, ee 值最高只有 68% (Scheme 12, a). 后来, 胡 文浩小组 [28] 利用和我们类似的策略, 实现了香豆素氧 化吲哚双螺环结构的快速构建(Scheme 12, b). 另外, 我 们 [29] 利用金对炔烃的独特活化能力, 实现了炔烃对金…”