Stereoarrays with an All-Carbon Quaternary Center: Diastereoselective Desymmetrization of Prochiral Malonaldehydes
作者:Bruno Linclau、Elena Cini、Catherine S. Oakes、Solen Josse、Mark Light、Victoria Ironmonger
DOI:10.1002/anie.201107370
日期:2012.1.27
The MgBr2 chelation of prochiralmalonaldehydes allows diastereoselective monoaddition reactions with allyl stannane nucleophiles (see scheme; PG=protecting group, TBDMS=tert‐butyldiphenylmethylsilyl, Tr=trityl). In the same pot, addition of a second nucleophile proceeds in high diastereoselectivity to generate nonsymmetric products with up to five contiguous stereogenic centers, including a chiral all‐carbon
Tris-1,1,1-(hydroxymethyl)ethane 1 was converted to a series of mono- and disubstituted derivatives. An indirect protocol for the differentiation of the alcohol groups was employed for the synthesis of partially and fully differentiated 1 containing a protected aldehyde unit. Complete differentiation of the alcohol groups was also achieved using a direct strategy (two steps from 1). The first synthesis of 1,3-dialclehydes derived from 1 is reported in two steps. (C) 2004 Elsevier Ltd. All rights reserved.