Platinum-Catalyzed Tandem Cycloisomerization Reaction of Benzoendiynyl Esters: Regioselective Long-Range 1,5-Acyl Migration

Abstract

A Pt(II)-catalyzed intramolecular chemo- and regioselective pentannulation/long-range 1,5-acyl migration reaction is described. This cascade cycloisomerization protocol produces a wide variety of benzofulvene diketones in good to excellent yields with exclusively the Z configuration of the exocyclic double bond of the final product. The (18)O isotope experiment together with (13)C NMR, HRMS, and HMBC analyses confirmed an interesting long-range acyl rearrangement process in this transformation.

Au-Catalyzed Hexannulation and Pt-Catalyzed Pentannulation of Propargylic Ester Bearing a 2-Alkynyl-phenyl Substituent: A Comparative DFT Study

“…The necessity of this excess energy in pathway-4 makes it unfavorable with respect to pathway-2 and thus does not allow the formation of naphthyl moiety (hexannulation_), which is consistent with the experimentally observed fact. 9…”

Insights into the Gold‐Catalyzed Propargyl Ester Rearrangement/Tandem Cyclization Sequence: Radical versus Gold Catalysis—Myers–Saito‐ versus Schmittel‐Type Cyclization

“…Gold(III) was also able to catalyze the reaction in as imilari someric ratio as [IPrAuNTf 2 ]b ut only in lowy ields (entry 11). As an ext step, different solvents were tested (entries [12][13][14][15]. Even though in toluene we could observe an increase in the isomeric ratio towards the 6-endo-dig cyclization product (entry 13), the overall obtained yield wasn ot satisfying.…”

“…[14] Just recently Chen et al published ap latinum-catalyzed reaction using as imilar 1,3-acyl migrations trategyt oo btain benzofulvenes also through aS chmittel-type enyne-allene cyclization (Scheme 1d). [15] Compared to the previously described reactions, which proceed through at andemc yclization cascade in which both independents teps are postulated to be transition-metal-catalyzed,S hi et al reported at andemr eactioni nw hicht he seconds tep is an uncatalyzed radical Schmittel cyclization (Scheme 2a). [16] In this case the pivotali ntermediate, the enyne-allene,i sg enerated by ag old-catalyzed propargyl vinyl rearrangement with at riazole gold catalyst.…”

“…Just recently Chen et al. published a platinum‐catalyzed reaction using a similar 1,3‐acyl migration strategy to obtain benzofulvenes also through a Schmittel‐type enyne–allene cyclization (Scheme d) 15…”

Transition-Metal-Catalyzed Highly Selective Electrophilic Cycloisomerization Reaction of Multi-alkynyl Compounds

“…和密集多取代的萘衍生物 [10] . 此外, 我们还发现具有缺 电子属性的羰基碳原子也可作为分子内亲电试剂, 在过 渡金属铂催化剂的作用下, 1,6-二炔酯类化合物可发生 分子内亲电环异构化反应, 高化学和区域选择性地构建 亚甲基茚二酮类化合物 [11] , 机理研究表明此反应的历程 涉及到一个分子内的 [3,3]-重排/五元环化/超远程 1,5-酰 基迁移的历程. 最后, 我们还发现 1,5-二炔类化合物可 在三氯化铋或对甲苯磺酸的作用下, 与三氟甲硫基苯胺 发生串联环化反应, 高选择性地得到了亚甲基三氟甲硫 基茚衍生物 [12] .…”