Masked Formylation with 2-Benzotriazolyl-1,3-dioxolane, a Novel Formyl Cation Equivalent

Five‐Membered Heterocycles with Three Heteroatoms: Triazoles

“…1-(Chloromethyl)benzotriazole reacted with sodium dialkyl phosphites to give dialkyl-(1-benzotriazolmethyl)phosphonates 123, which are potential Horner-Emmons reagents [178] for the stereoselective preparation of (E)-1-(1-alkenyl)benzotriazoles [179]. 2-Benzotriazolyl-1,3-dioxolane (124) has been utilized as a novel formyl cation equivalent [180]. The novel three-carbon synthon 1-(1H-1,2,3-benzotriazol-1-yl)-3-chloroacetone (125) (112), and alkylthio- (113) methylbenzotriazoles [167].…”

Direct Synthesis of Protected Arylacetaldehydes by Tetrakis(phosphane)palladium‐Catalyzed Arylation of Ethyleneglycol Vinyl Ether

“…The major isomer was purified by chromatography on silica gel. Cyanobenzyl)-1,3-dioxolane (7d): [42] Isomer 7d was obtained in 92 % (0.174 g) isolated yield. Nitrobenzyl)-1,3-dioxolane (8d): [43] Isomer 8d was obtained in 87 % (0.182 g) isolated yield.…”

“…[44] Isomer 9d was obtained in 90 % (0.209 g) isolated yield. 1 [42] and Products 11b, 11c and 11e: A mixture of isomers 11b-e was obtained in 87 % (0.191 g) isolated yield. …”

Selective and Efficient Formylation of Indoles (C3) and Pyrroles (C2) Using 2,4,6‐Trichloro‐1,3,5‐Triazine/Dimethylformamide (TCT/DMF) Mixed Reagent

“…Moreover, during the multistep synthesis of many natural products, formylation reaction is often necessary, and the selectivity, simplicity, and efficiency of this step are highly critical . Some of the widely used formylating agents that have been reported up to now are POCl 3 / N , N ‐dimethylformamide (DMF) , HCO 2 H/ N,N′ ‐Dicyclohexylcarbodiimide (DCC) , 2,2,2‐trifluoroethyl formate , formic acid/1‐Ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide (EDAC) , acetic formic anhydride , formyl‐pivaloyl anhydride , cyanomethylformate , pentafluorophenyl formate , imidazole/DMF , MeOH/Ru , CO 2 /PhMe 2 SiH , AgOTf/Cl 2 CHOMe , tetramethylethylenediamine/O 2 /visible light , FeCl 3 /DMSO , CO/acid , 2‐benzotriazolyl‐1,3‐dioxolane , N ‐methyl aniline/Ru , Pd/CO/H 2 , tert ‐butyl isocyanide , Pd/CH 3 NO 2 , etc. In spite of the diversity of formylating agents, there are serious restrictions for the preparation of some of them, such as harsh experimental conditions, the use of unusual reagents, formation of unwanted or toxic byproducts, use of expensive procedures for their synthesis, and thermal instability of the reagents.…”