2-Propenylmagnesium chloride 2-

Propenylmagnesium Chloride, Catalyzed by a Magnesium-Anthracene-THF Complex (Method A) Typical Procedure1,1 ... 

Propenylmagnesium Chloride from Mechanically Activated Magnesium (Method B) General Procedure16 ... 

The complex 8, formed by the addition of 2-propenylmagnesium chloride to 7, adds to aromatic aldehydes, 1-alkanals, a-branched and unbranched alkanals uniformly from the 7 c-face leading to hoinoallylic alcohols with 88-94% ee35 (Method A). After hydrolytic workup, both components can be recycled. Allyl complexes 10, generated from 9, prefer 67-attack and lead to the ent-homoallylic alcohols with excellent enantioselectivity36 (Method B) (Table 8). 

The reaction of 2-methyl-2-propenylmagnesium chloride with the allenic aldehyde 342 (from isobutyraldehyde and 2-methyl-3-butyn-2-ol) gave the precursor 343 for an internal [2 + 2] cycloaddition. After oxidation and irradiation, the bicyclo[3.2.0]heptanone 324 obtained was converted to ( )-lineatin [( )-... 

Stock solutions of 2-propenylmagnesium bromide (1-2 M) in diethyl ether and 2-propenyl-magnesium chloride in THF are commercially available. 

The reactions of a-methyl-branched acylsilanes with 2-propenylmagnesium bromide exhibit surprisingly high diastereoselectivilies, although further improvement is accomplished by application of allyltrimethylsilane/ titanium(IV) chloride (> 100 I)27. The fluoride-induced desilylation proceeds with retention of configuration. 

The direct allylation of 2-phenylpropanal proceeds with much lower selectivity [2-propenylmagnesium bromide 73 27 allyltrimethylsilane/titanium(IV) chloride 67 33]27. 

Reduction of prochiral 1,3-diketone A with baker s yeast gives hydroxy ketone B of 99% ee.10 The ketone B was converted to unsaturated ketone C, which was treated with (Z)-l-propenylmagnesium bromide in the presence of cerium(III) chloride to give a mixture of D and E. This mixture was directly subjected to oxy-Cope rearrangement to give F from D. The exo-isomer E was recovered unchanged. 

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