Stabilisation de molecules hyperactives par complexation: Le formyl-2 butadiene fer-tricarbonyle. Preparation, dedoublement et reactivite

Synthesis and Applications of Tricarbonyliron Complexes of Dendralenes

“…The complexation of unstable dienes by the Fe(CO) 3 group to generate stable complexes is well established. [6][7][8] Nevertheless, the preparation and reactions of metal complexes of dendralenes has been poorly investigated, [9][10][11] with only one early study describing direct complexation of a dendralene. [9] We found that the tricarbonyliron complex of [3]dendralene 2 could be readily prepared in good yield on a multigram scale through an azabutadiene-catalyzed [12] reaction of Fe 2 (CO) 9 with the parent hydrocarbon 1 (Scheme 2).…”

Diastereoselective Allylations of Enantiopure 3- and 4-Substituted η4-(1Z)-(Sulfinyldienal)iron(0) Tricarbonyl Complexes

“…Our attention next turned to cases in which the position of the aldehyde and the bulky substituent were transposed, that is, allylation of sulfinyl iron dienals 12a and 12b (Table , entries 6 and 7). Diastereoselective addition of alkyllithiums (80:20 to 92:8), Grignards (63:37), and zinc−copper reagents (73:27 to 95:5) 11 to η 4 -(2-formyl-1,3-butadiene)iron(0) tricarbonyl complexes have been demonstrated to occur via an s-cis aldehyde conformation; similarly, LiAlH 4 reduction of the corresponding methyl ketone has also been shown to proceed preferentially (71:29) via the s-cis conformer …”

A Rapid Access to New Fluorinated 1,3-Dienes and Benzylic Fluorides via Metathesis on Propargylic Fluorides

“…7 However, the iron complexes corresponding to 1,3-butadien-2-ylmethanols are available in optically active form only after tedious resolution processes. 8 On the other hand, synthesis of type 6 dienes would be also very challenging, especially if one considers the gem-difluorination of the corresponding 1,3-dien-2-ones. 8 First of all, such derivatives are known to be unstable, prone to dimerization processes, 9 and isolated mostly as the corresponding iron-tricarbonyl complexes.…”

“…8 On the other hand, synthesis of type 6 dienes would be also very challenging, especially if one considers the gem-difluorination of the corresponding 1,3-dien-2-ones. 8 First of all, such derivatives are known to be unstable, prone to dimerization processes, 9 and isolated mostly as the corresponding iron-tricarbonyl complexes. 8 Moreover the gem-difluorination of enones is known to be very challenging and the desired compounds are obtained only in very poor yields, except when using ultra high pressure reaction conditions.…”

“…8 First of all, such derivatives are known to be unstable, prone to dimerization processes, 9 and isolated mostly as the corresponding iron-tricarbonyl complexes. 8 Moreover the gem-difluorination of enones is known to be very challenging and the desired compounds are obtained only in very poor yields, except when using ultra high pressure reaction conditions. 10 In view of the importance of the benzylic fluorides and our efforts to develop efficient synthesis of novel fluorinated key intermediates 11 which could act as useful building blocks, we became interested in designing a new strategy for these benzylic fluorides.…”