DABCO‐Mediated C−O Bond Formation from C_sp2‐Halogen Bond‐Containing Compounds and Alkyl Alcohols

Abstract

An efficient protocol for CÀ O bond formation from C sp2 À X (X=Br, Cl) bond-containing compounds and alkyl alcohols in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) as catalyst and base under mild conditions is described. The densely functionalized 2(5H)-furanone products can be generally obtained in moderate to excellent yields via a metal-free protocol at room temperature without added solvent.

Aromatic Aza‐Claisen Rearrangement of Arylpropargylammonium Salts Generated in situ from Arynes and Tertiary Propargylamines

“…The above reactions provided a variety of multisubstituted 2‐proparylanilines bearing functional groups such as trifluoromethoxy, amide, sulfonamide, halo, cyano, ketone, and ester. Although amides, sulfonamides, and esters were reported previously to undergo addition or insertion into arynes, [8a–d,j] in our cases they were well tolerated due to their much lower nucleophilicity relative to tertiary amines. Interestingly, very high site selectivity was observed in the synthesis of 2‐proparylaniline 3 v , wherein the N ‐propargyl group participated in the aromatic aza‐Claisen rearrangement, and in sharp contrast, the N ‐allyl group did not at all (Table 1, entry 21) [16] .…”

C4‐Selective Synthesis of Vinyl Thiocyanates and Selenocyanates Through 3,4‐Dihalo‐2(5H)‐furanones

“…In order to improve the reaction efficiency, we carried out the reaction with the use of various bases (Table , entries 11–15), including 1,4‐diazabicyclo[2.2.2]octane (DABCO) Surprisingly, this approach is found to be feasible and simple NaHCO 3 is the most suitable base for the present transformation (entry 15). Further optimization was carried out with different amounts of this inexpensive base (entries 15–19).…”

“…All reagents and solvents were purchased from commercial sources and used without further purification. Different 5‐alkoxy (aryloxy) 3,4‐dihalo‐2(5 H )‐furanone intermediates were synthesized according to the literature procedure , , …”

Research Progress in C—S Bond Formation Reaction of Olefins with Organic Sulfur Reagents under Photocatalyst-Free and Non-Electrochemical Conditions

“…应性质 [75][76][121][122] 及合成应用 [123][124][125] 一直是个令人感兴 趣的课题 [74] , 本课题组 [126] 也开发了 3,4-二卤-2(5H)-呋 喃酮与亚磺酸钠的砜基化反应(Eq. 51).…”