equivalent, 1 was investigated in the thioacetalization reaction. Various types of aldehydes and ketones 3 were converted to the corresponding dithianes 4 in the presence of 1 in high yields (79-97%). Moreover, 1 exhibited obvious chemoselectivity betweenaldehyde and ketone in this thioacetalization reaction. A mechanism for this thioacetalization reaction is proposed.
3-Amino-4-iodothiophenes are obtained by iodocyclization of 1,3-dithianyl substituted propargylamine derivatives through iodine induced cleavage of dithiane ring in a bicyclic sulfonium intermediate. 1-(1,3-Dithian-2-yl)propargylamines are readily available by Au-catalyzed reaction of 1,3-dithiane-2-carbaldehydes, amines, and alkynes in a one-pot.
3-氨基-4-碘噻吩是通过碘代环化1,3-二噻吩基取代炔丙胺衍生物通过碘诱导的双环锍中间体中的二噻烷环裂解获得的。1-(1,3-Dithian-2-yl) 炔丙胺很容易通过 1,3-二噻烷-2-甲醛、胺和炔烃在一锅中的 Au 催化反应获得。
Tandem Carbon−Carbon Bond Constructions via Catalyzed Cyanation/Brook Rearrangement/C-Acylation Reactions of Acylsilanes
作者:Xin Linghu、David A. Nicewicz、Jeffrey S. Johnson
DOI:10.1021/ol0263649
日期:2002.8.1
see text] A tandem nucleophile-catalyzed cyanation/Brookrearrangement/C-acylation has been developed. Phase transfer cocatalysts facilitate cyanide-catalyzed reactions between acylsilanes and cyanoformates to afford protected tertiary carbinol products. A catalytic cycle is proposed involving cyanation of an acylsilane, [1,2]-Brook rearrangement, and C-acylation of the derived carbanion by a cyanoformate
The first catalytic α-alkylation reaction of benzyl sulfides and 1,3-dithianes with styrenes and conjugated dienes was developed under mild conditions by using a readily available Brønsted base potassium bis(trimethylsilyl)amide (KHMDS) as catalyst. The reaction displayed good functional group tolerance, high efficiency, and excellent chemoselectivity. A series of desired alkylation products were obtained
Chemoselective (Trans)thioacetalization of Carbonyl Compounds with a Reusable Lewis Acid-Surfactant-Combined Copper Bis(dodecyl sulfate) Catalyst in Water
A Lewis acid-surfactant-combined copper bis(dodecyl sulfate) [Cu(DS)2] catalyst served as an efficient and reusable catalyst for the thioacetalization and transthioacetalization of carbonyl compounds and O,O-acetals in water at room temperature. Some of the major advantages of this procedure are high chemoselectivity, ease of operation and purification without any organic solvent, and high yields.