Vinyl triphenylphosphonium bromide

After the final filtration the product is washed with two 100-ml. portions of ethyl acetate and two 100-ml. portions of anhydrous ether and dried for 24 hours at 80°. The dried, analytically pure vinyl triphenylphosphonium bromide, m.p. 186-190°, weighs 122-158 g. (66-86%). 

The present procedure is that described by the submitters.2 Vinyl triphenylphosphonium bromide has also been prepared by... 

VINYL TRIPHENYLPHOSPHONIUM BROMIDE (Phosphonium bromide, triphenylvinyl-)... 

Caution Because phenol and its solutions are corrosive, rubber gloves should be used in the following operations. The product, vinyl triphenylphosphonium bromide, has been found to induce a sneezing, allergic reaction and contact with it should be avoided. 

A more concise route to ( )-cherylline was also devised and commenced with the reductive animation of isovanillin with methylamine followed by reaction of the intermediate benzylamine with vinyl triphenylphosphonium bromide to provide the aminophosphonium salt 619. Sequential treatment of 619 with n-butyllithium and the quinone ketal 615 followed by reaction of the resulting crude allylic amine 620 with boron trifluoride etherate gave the phenolic amine 618 in good overall yield (225). 

Vinylmagnesium bromide, 251 Vinylmagnesium chloride, 221, 572 Vinyl trifluoromethanesulfonates, 533 3-Vinyl-3,5,5-trimethylcyclohexanone, 221 Vinyl triphenylphosphonium bromide, 572 Vitamin A acetate, 16 Vitamin A alcohol, 372 Vitamin B, 2, 82... 

Vinyl triphenylphosphonium bromide, CHr=CHP(C6H5)3Br". Mol. wt. 269.24, m.p. 188-190°, the salt produces a sneezing allergic reaction. 

Vinyl laurate, 648-649, 1271 Vinyllithium, 1250, 1273-1274 Vinylmagnesium bromide, 213, 332 Vinylmagnesium chloride, 415 Vinylmagnesium halides, 418 2-Vinylthiophene, 960 Vinyl triphenylphosphonium bromide, 1274-127S Viscolizer, 434... 

Dihydropyridazine (36a) was prepared in moderate yield by treatment of substituted a-imino ketones with vinyl triphenylphosphonium bromide [Eq. (6)].88... 

Synthesis of five- and six-membered cycloalkenes has been achieved by the reaction of vinyl triphenylphosphonium bromide with ketomalonic esters of type (1), n = 1 to give 2[(2, n = 1) diethyl 3-methyl cyclopentenodicarboxylate]. 

DL-Valeric acid, 369 Vanadium oxyacetylacetonate, 456 Vanadyl acetylacetonate, see Vanadium oxyacetylacetonate Vanillin, 217 Veratrole, 116 a-Vetivone, 306 Vilsmeir reaction, 129 Vinylacetic acid, 428 crr-Vinylalanes, 141, 142 mww-Vinylalanes, 141, 142 Vinyl azides, 100 Vinyl halides, 142 Vinylidinebisdimethylamines, 400 Vinyl ketones, 71 Vinyllithium, 456 Vinylmagnesium halides, 91 Vinyl triphenylphosphonium bromide, 456-457... 

A number of cycloaddition reactions involving allene derivatives as dienophiles have been recorded. Allene itself reacts only with electron-deficient dienes but allene carboxylic acid or esters, in which a double bond is activated by conjugation with the carboxylic group, react readily with cyclopentadiene to give 1 1 adducts in excellent yield. For example, the allene 12 gave, with very high yield and selectivity, the cycloadduct 13, used in a synthesis of (-)-P-santalene (3.19). An allene equivalent is vinyl triphenylphosphonium bromide, which is reported to react with a number of dienes to form cyclic phosphonium salts. These can be converted into methylene compounds by the usual Wittig reaction procedure (3.20). 

Trimethyltinlithium in tetrahydrofuran added during 10 min. at -93 to vinyl-triphenylphosphonium bromide in ether, kept an additional 5 min. at -93 , titrated with cyclohexanone at the same temp, until the red color has disappeared, warmed slowly to room temp., treated with aq. HCl until 1.0 M, and allowed to stand ca. 10 hrs. at room temp. vinylcyclohexane. Y 90%. S. J. Hannon and T. G. Traylor, Chem. Commun. 1975, 630. 

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