The asymmetric conjugate addition of various carbon and heteroatom nucleophiles to nitroalkenes as a tool for the construction of highly functionalized synthetic building blocks is presented. Diastereoselective, substrate-controlled 1,4-additions are also included. Besides auxiliary controlled asymmetric Michael additions, external asymmetric versions employing enantiopure additives, addition-elimination processes with enantiopure leaving groups, and catalytic asym-

A highly efficient, diastereo-and enantioselective route was developed to access a great variety of lignans. The asymmetric synthesis of the 2,3-disubstituted g-butyrolactones 9a-c could be improved in the case of aldol reactions by employing 2.2 equivalents of LiCl as an additive to provide, after purification, highly diastereo-and enantioenriched starting materials for the synthesis of the furofuran lignans (-)-methyl piperitol, (-)-sesamin, and (-)-aschantin. Furthermore, the g-butyrolactone 15 was converted into dibenzylbutyrolactone lignan (+)-yatein, the dibenzylbutandiol type (+)-dihydroclusin, the tetrahydrofuran type (+)-burseran, and the dibenzocyclooctadiene type (-)-isostegane.

The right choice of sugar auxiliary led to a breakthrough in the first asymmetric α‐alkylations of sulfonic acid esters (see scheme). The high asymmetric inductions were reached with 1,2:5,6‐di‐O‐isopropyliden‐α‐D‐allofuranose as the auxiliary group, which can be cleaved off again under mild conditions. Enantiopure α‐substituted methyl sulfonates are important building blocks and precursors of bioactive compounds.

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A novel asymmetric synthesis of highly enantioenriched homotaurine precursors has been developed via diastereo-selective Michael addition of lithiated enantiopure sulfonates to nitroalkenes by using 1,2:5,6-di-O-isopropylidene-alpha-D-allofuranose as chiral auxiliary.