Regio- and stereoselective hydration

Regio- and Stereoselective Hydration of Alkenes by Hydroboration Another functional group interconversion involving addition. 

REGIO- AND STEREOSELECTIVE HYDRATION OF UNSATURATED FATTY ACIDS... 

The microsomal epoxide hydrolases (microsomal EH, mEH), predominantly found in the endoplasmic reticulum, regio- and stereoselectively catalyze the hydration of both alkene and arene oxides, including oxides of polycyclic aromatic hydrocarbons. These enzymes have been purified to homogeneity from various species and tissues [22] [41 - 46], The human microsomal EH contains 455 amino acids (Mr 52.5 kDa) and is the product of the EPHX1 gene [47] (also known as HYL1 [48]). 

However, various attempts to introduce stereospecifically the a-hydroxyl group at the desired position of the double bond by hydroboration were unsuccessful. Eventually hydration of the double bond was accomplished by mercuration-reduction protocol, which although occurring both with high regio and stereoselectivity furnished only the p hydroxy compound 339. The conversion of the latter with formaldehyde into ( )-epielwesine (335) constituted in a formal sense, the synthesis of ( )-elwesine (320) as well, since Sanchez et al 88 had shown that the inversion of the hydroxyl group in 335 could be accomplished with diethylazodicarboxylate, triphenylphosphine and formic acid. 

Introduction Chemo-, Regio-, and Stereoselectivity Chemoselectivity Controlling Chemoselectivity Regioselectivity Markovnikov Hydration Mercuration-reduction Wacker oxidation... 

Hydroboration-oxidation of alkenes is a valuable laboratory method for the regio-selective and stereoselective hydration of alkenes. Furthermore, this sequence of reactions occurs without rearrangement. 

Gao D, O Doherty GA. Total synthesis of fostriecin via a regio and stereoselective polyene hydration, oxidation, and hydroboration sequence. Org. Lett. 2010 12 (17) 3752-3755. 

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