Diethoxytriphenylphosphorane

Diethoxytriphenylphosphorane (the product of insertion of triphenylphosphine into diethyl peroxide) finds use as a mild, neutral reagent which initiates cyclodehydration of N- and C-substituted g-aminoalcohols to form aziridines in excellent yield,... 

The pioneering work of Denney et ai19 on the synthetic utility of oxyphosphoranes has been thoroughly exploited by Evans et al. in demonstrating that diethoxytriphenylphosphorane promotes mild and efficient cyclodehydration of diols (e.g. 11) to cyclic ethers (e.g. 13) via the cyclic phosphorane (12)20>21. Simple 1,2-, 1,4-, and 1,5- diols afford good yields of the cyclic ethers but 1,3-propanediol and 1,6-hexandiol give mainly 3-ethoxy-l-pro-panol and 6-ethoxy-l-hexanol respectively whereas tri- and tetra-substituted 1,2-diols afford the relatively stable 1,3,2- diox-phospholanes. In some instances (e.g. 14), ketones (e.g. 16) are formed by a synchronous 1,2-hydride shift within (15). The synthetic utility has been extended to diethoxyphosphoranes supported on a polystyrene backbone22. 

Diethoxytriphenylphosphorane, (C6H5),P(OC2H5)2 (1). The phosphorane is obtained by reaction of diethyl peroxide (caution) with triphenylphosphine at 0-70°. Cyclodehydration of dioIs to ethers. 1,3-, 1,4-, and 1,5-Diols react with 1 to... 

Trimethylamine N-oxide, 325 Vinyltrimethylsilane, 343 Other reactions (Phenylsulfonyl)allene, 247 Cyclodehydration Diethoxytriphenylphosphorane, 109 Hexamethylphosphoric triamide, 142 Cycloprop anation Simmons-Smith reaction Diiodomethane-Diethylzinc, 276 Simmons-Smith reagent, 275 by other reagents which add CH2 to a carbon-carbon multiple bond Dibromomethane-Zinc-Copper(I) chloride, 93... 

Rearrangement of 1,2-disubstituted compounds Diethoxytriphenylphosphorane, 109 epoxides to allylic alcohols Methylmagnesium N-cyclohexylisopro-pylamide, 189... 

Tetraethylammonium iodide, 46 Triphenylphosphine-Diethyl azodi-carboxylate-Lithium halides, 332 of alcohols by nitrogen nucleophiles Dichlorotris(triphenylphosphine)-ruthenium(II), 107 Diethoxytriphenylphosphorane, 109 Diphosphorus tetraiodide, 127 Triphenylphosphine-Diethyl azodicar-boxylate, 332... 

Diethoxytriphenylphosphorane, 109 Diisobutylaluminum hydride, 115 Diphosphorus tetraiodide, 127 Hexamethylphosphoric triamide, 142 (S)-( - )-Menthyl p-toluenesulfinate, 173... 

Diethoxytriphenylphosphorane, 109 Diphosphorus tetraiodide, 127 Phenyl azide-Aluminum chloride, 240 Triphenylphosphine-Diethyl azodicar-boxylate, 332... 

Meldrum s acid, 172 Tin(IV) chloride, 300 Containing two oxygens N-Bromosuccinimide, 49 Other six-membered heterocycles Diethoxytriphenylphosphorane, 109 Miscellaneous heterocycles of any ring size... 

Murray, W.T., Kelly, J.W., and Evans, S.A., Jr., Synthesis of substituted 1,4-oxathianes, mechanistic details of diethoxytriphenylphosphorane — and triphenylphosphine/tetra-chloromethane — promoted cyclodehydrations and 13C NMR spectroscopy, J. Org. Chem., 52, 525, 1987. 

The scope and synthetic utility of dioxyphosphoranes, and particularly, diethoxytriphenylphosphorane (DTPP), as useful cy-clodehydrating "reagents" for the conversion of diols to cyclic ethers have received only superficial attention (1). The DTPP-diol - ether route has several unique advantages over existing methods (a) the reaction conditions are effectively neutral and mild, (b) the stereoselectivity in the closure of both unsymmet-rical and symmetrical diols to cyclic ethers is high, and (c) the isolation of the product(s) from triphenylphosphine oxide (TPPO) is convenient. 

TPP=triphenylphosphine DTPP=diethoxytriphenylphosphorane TPP0= triphenylphosphine oxide i GLC= gas-liquid chromatography. 

Reagents formed by combining PhjP with CCU and with diethyl azodicarboxylate (DEAD) promote cyclization of amino alcohols to cyclic amines (Scheme 26). Various 2-amino alcohols reacted with diethoxytriphenylphosphorane (66) to afford the corresponding aziridines in 85-90% yields. The reaction proceeds with retention of the configuration at the amino carbon (C-2) (Scheme 26). In view of... 

Diethoxytriphenylphosphorane, (C6H5)3P(OC2H5)2 (1). The reagent is obtained as a viscous oil by reaction of ( 5115)3 with diethyl peroxide in CH2CI2. It can be prepared conveniently and stored indefinitely in toluene at 25° (N2). 

Oxirans. - Methyl a-D-glucopyranoside has been oxaphosphoranylated with diethoxytriphenylphosphorane and the product mixture was thermolysed to give epoxides (18) and (19). The thermolysis was accelerated by the presence of LiBr, and in this case only epoxide (18) was obtained. An improved five-step synthesis of methyl 2,3-anhydro-a- and P D-lyxofuranosides from D-xylose reports no need for intermediary purifications. ... 

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