Embolization decreases the risk of VV recurrence after surgery and also improves PCS symptoms in women with VV in lower limbs and IPV.

Alpha,beta-unsaturated esters were obtained with complete control of stereoselectivity utilizing a sequential reaction of dichloroesters with a variety of aldehydes, promoted by active manganese. This methodology is generally applicable, and the C-C double bond can be di- or trisubstituted. A mechanism based on a successive aldol-type reaction/beta-elimination is proposed to explain these results.

A complete E-selective synthesis of alpha,beta-unsaturated amides through a sequential reaction of a range of dichloroamides with a variety of aldehydes promoted by Rieke manganese (Mn*) is reported. A mechanism based on a sequential aldol-type reaction and a completely stereoselective beta-elimination is proposed to explain these results. The unsaturated amides obtained are readily and efficiently transformed into alpha,beta-unsaturated ketones, aldehydes, or carboxylic acids without loss of the diastereoisomeric purity of the C-C double bond.

A study of the advantages of using manganese, an inexpensive and nontoxic metal, to perform stereoselective b-elimination reactions and to promote sequential olefination reactions of aldehydes to obtain a,b-unsaturated esters and amides is presented. Various elimination reactions, all of them characterized by occurring with complete stereoselectivity and in high yields, were performed using active manganese (Mn*) as metalating agent. This ability of manganese has been applied to develop a novel and direct synthesis of (E)-a,b-unsaturated esters or amides and (Z)-a,b-unsaturated a-halo esters and a-choroamides through a Mn*-mediated sequential olefination protocol of aldehydes with dichloro esters or amides and trihalo esters or trichloroamides, respectively.Manganese is a nontoxic 1 and inexpensive 2 metal and the reduction potential of Mn 2+ /Mn 0 system (-1.03 V) 3 is adequate to reduce an important number of organic functions. According to these properties, extensive use of manganese in organic synthesis might be expected. However, in contrast to other metals, such as lithium, magnesium, zinc, or samarium, the application of manganese in organic synthesis has been scarcely developed. Among the main reasons for this lack of development are the inability of commercially available manganese to react directly with organic compounds as consequence of its passivity, 4 mainly because of the formation of an oxide layer on its surface. To overcome the lack of reactivity of manganese metal, different procedures have been describe to obtain active manganese (Mn*) by Rieke 5 and Fürstner 6 in 1996, by Oshima 7 in 1998, and by Cahiez 8 in 1999. Since then the number of reported transformations promoted by Mn* have increased. 9 It is important to note that all these transformations take place with high selectivity. Combining the aforementioned properties of manganese (reduction potential, selectivity, low price, and toxicity) with our interest in the development of novel highly selective organic reagents, including the use of selective metals, has prompted us to develop new synthetic applications of manganese.We decided to test the ability of manganese to promote highly stereoselective elimination reactions towards the synthesis of a,b-unsaturated esters or amides, based on: (a) the use of manganese to carry out elimination reactions has not been previously reported, and (b) despite there being a large number of contributions reporting the synthesis of a,b-unsaturated esters 10,11 or amides, 11,12 some of these methods take place without complete stereoselectivity (particularly when the double bond is trisubstituted) and are either tedious (multistep procedures) or imply the use of expensive starting materials.Based on these precedents, we reported the first transformation of 2-bromo-3-hydroxy esters into a,b-unsaturated esters with complete stereoselectivity promoted by commercial manganese activated by chlorotrimethylsilane. 13 Later, we described a novel manganese-mediated olefination reaction of aldehydes to obtain (E)-...

E-a,b-Unsaturated ketones can be obtained with complete E-selectivity by a sequential reaction of dichloroketones with a variety of aldehydes. This transformation was promoted by SmI 2 , SmI 2 in the presence of FeCl 3 or CrCl 2 . The best results were obtained when CrCl 2 was used as the metallating agent. A mechanism based on a successive aldol-type reaction and a b-elimination is proposed to explain these results.

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A simple and general methodology directed towards the synthesis 3-aryl-2-hydroxy amides, or esters with total regioselectivity from the easily available 2,3-epoxy amides or esters, promoted by active manganese is described. Utilizing enantiopure epoxy amides as starting materials, the corresponding 3-aryl-2-hydroxy amides in enantiopure form are also available. Some synthetic applications of selected examples of 3-aryl-2-hydroxy carboxylic acid derivatives are shown. A mechanism has been proposed to explain this novel reaction.

Preliminary results of a Mn-promoted sequential process directed toward the stereoselective synthesis of different (Z)-alpha-halo-alpha,beta-unsaturated compounds are described.