Boron Trifluoride Etherate bromination

Aluminum phosphide Amyl trichlorosilane Benzoyl chloride Boron tribromide Boron trifluoride Boron trifluoride etherate Bromine pentafluoride Bromine trifluoride n-Butyl isocyanate Butyllithium Butyric anhydride Calcium Calcium carbide Chlorine trifluoride Chloro silanes Chlorosulfonic acid Chromium oxychloride Cyanamide Decaborane Diborane... 

Epinephryl borate Boron trifluoride etherate Nimetazepam Bromine... 

Boron trifluoride etherate, co-catalyst, 53, 30, 32 a-Bromination, selective of aralkyl ketone, 53, 111 Bromine, with 3-chlorocyclo-butanecarboxylic acid and mercuric oxide to give 1-bromo-3-chlorocyclobutane, 51, 106... 

Reports) was converted (by a modified Curtius reaction) into the corresponding isocyanate, which was cyclized in 70—90% yield into the lactam (26), using boron trifluoride etherate. Since these represent new conditions for effecting such a reaction, generalization to a number of substituted phenethyl isocyanates was carried out. Compound (26), upon successive acetoxybromination, dehydro-bromination, and hydrolysis, gave the target compound (27), whose quasi-axial a-OH configuration was deduced from n.m.r. data. 

A convenient synthesis of 4-methyl- and 4-phenylseleno-l,l,l-trihalo-3-alken-2-ones 74 from the reaction of the corresponding 4-methoxy-l,l,l-trihalo-3-alken-2-ones 73 with methyl- or phenylselenols in the presence of boron trifluoride etherate was reported. The reaction of 74 (R = Me) with bromine followed by ammonia led to 3-trihalomethyl-isoselenazoles in good yields (Scheme 26) <2002S2220>. 

The most recent work on styrene [102] has been carried out in benzene solution with initiation by boron trifluoride etherate, BF3 0(C2H5)2. An accurate estimate of the number of active centres, [P ], was achieved by a method similar to that used in Saegusa et al. [45] in ring opening polymerizations (see Section 7.1). Reactions were prematurely terminated by addition of 2-bromothiophene, and the bromine content of the polymers produced estimated by radio activation analysis. Application of the simple relationship (which assumes rapid initiation)... 

Dehydration of the optically active relay (178) derived from enmein (62) gave a 1 2 mixture of 5,6-ene and 6,7-ene. Separation could be achieved by means of the ethylene acetal (187), whose ozonolysis product was subjected to successive Jones oxidation, methylation, Wittig reaction, and treatment with dilute hydrochloric acid to afford the 3-on-16-ol derivative (188). Bromination of (188) followed by dehydrobromination and subsequent dehydration afforded (189). The purified compound (189), after conversion into the acetal, was hydrolyzed to carboxylic acid (190), which was transformed into the desired lactone (191) by treatment with boron trifluoride etherate. The reaction produced a single product uncontaminated by the C-1 epimer, because of easy formation of a favored transition state which satisfied the stereoelectronic requirements. 

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