Phenylmagnesium bromide 2.4.6- trimethyl

One notable advance in this chemistry since the publication of CHEC-II(1996) is the use of enantiomerically enriched 3,6-dihydro-l,2-thiazine 1-oxides in the rearrangement sequence. For instance, iV-Cbz-protected bicyclic 1,2-dihydrothiazine 44 undergoes ring opening upon treatment with phenylmagnesium bromide (Scheme 16). The synthesis of allylic amino alcohol 129 is completed in excellent yield upon exposure of the intermediate sulfoxide 130 to trimethyl phosphite and methanol at 80 °C <2002TA2407, 2000TL3743>. 

The 2-[3-(a-hydroxybenzyl)-2-thienyl]-3,4,4-trimethyl-2-oxazolinium iodide (335) reacted with phenylmagnesium bromide to give 4,6-diphenylthieno[2,3-c]furan (130) (85% yield) <89CBlll9>. 

Magnesium anthracenide (9.10-dihydro-9,10-anthracenediyl)tris(tetrahydrofuran)magnesium) Mesitylmagnesium bromide (2,4,6-trimethyl-phenylmagnesium bromide) 4-Methoxyphenylmagnesium bromide Methylmagnesium bromide... 

When N-sulfinylcarbamate 224 was reacted with ( , )-2,4-hexadiene 225 the formal [4 -I- 2] cycloaddition products (the reaction mechanism is a matter of debate [141-143]) 226 and epi-226 were formed in a 15 1 ratio, respectively. Treatment of this mixture with phenylmagnesium bromide followed by refluxing the resulting mixture with trimethyl phosphite in methanol af-... 

Reaction of Phenylmagnesium Bromide with Boronic Acid Trimethyl Ester... 

Table 8.5 Product selectivity of the reaction of phenylmagnesium bromide with boronic acid trimethyl ester...

It has been reported that the adduct of N-sulfinylaniline and 2,3-di-methylbutadiene is stable to ethylmagnesium bromide.23 However, Weinreb and co-workers36-38,52 have recently found that a number of N-acyldihydrothiazine oxides are susceptible to ring opening by a variety of reactive carbon nucleophiles. For example, when dihydrothiazine oxide 44 was treated with phenylmagnesium bromide, followed by trimethyl phosphite, (EJ)-threo-hydroxycarbamate 45 was produced exclusively [Eq. (24)].36... 

The Weinreb group has recently developed stereoselective methodology for synthesis of unsaturated vicinal diamine derivatives from dihydrothiazine imines.49 For example, when cycloadduct 54 prepared from (E, )-2,4-hexadiene was treated with phenylmagnesium bromide followed by trimethyl phosphite, E-threo vicinal diamine 57 was formed cleanly in good yield [Ea. <27)1. 

An ethereal soln. of dineopentyl ketone added during 2 hrs. to 2,4,6-trimethyl-phenylmagnesium bromide prepared from bromomesitylene and Mg in ether, refluxed 2 hrs., then acetic anhydride in ether added during 2 hrs. with icecooling, and stirring continued 1 hr. - 2,2,6,6-tetramethylhept-3-en-4-yl acetate. Y 90%. F. e. s. H. G. Hauthal, P. Kluge, and H. Schmidt, J. pr. 29, 296 (1965). 

In 1942 Fuson et al. [83] observed that in the reaction of phenylmagnesium bromide with 2,4,6-trimethylbenzophenone a ring-substitution product, 2,4,6-trimethyl-2 -phenyl-benzophenone, was formed, apparently as the result of a 1,4-addition reaction. 

Similar nucleophilic substitution at phosphorus with the loss of alkoxide instead of halide vide supra) also occurs readily. Thus, under a nitrogen atmosphere (to avoid oxidation at phosphorus) when four or more equivalents of phenylmagnesium bromide are treated with trimethyl phosphite (Equation 10.75), triphenylphosphine is cleanly obtained. However, if three or fewer equivalents of the same Grignard reagent are used, then dimethyl phenylphosphonite, methyl diphenylphosphinite, and triphenylphosphine are all found (Equation 10.76) with the exact ratio being. 

Clariant GmbH in Frankfurt, Germany, performed the synthesis of phenylboronic add from phenylmagnesium bromide and boronic acid trimethyl ester on a pilot-... 

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