The First Highly Efficient Asymmetric Synthesis of α-Substituted Methyl Sulfonates

Abstract

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.

Asymmetric Synthesis of -Substituted N-Methylsulfonamides

“…HMPA, TMEDA, and i Pr 2 NH were distilled from CaH 2 and kept under Ar. The sodium sulfonate (R)-21 was prepared from the corresponding methyl sulfonate [20]. chloride (1.1 equiv.…”

Asymmetric Synthesis of Allylic Sulfonic Acids: Enantio‐ and Regioselective Iridium‐Catalyzed Allylations of Na2SO3

“…In 1992, Corey for the first time reported an (R)-1-phenylethanesulfonic acid derived from an enantiopure alcohol in multistep reactions. [14] Biller [8] and Enders [15] synthesized chiral sulfonic acids by using a chiral auxiliary, which induced an asymmetric sulfonation at the adjacent carbon atom. Adamo [16] and Peters [17] reported cinchona alkaloid-catalyzed asymmetric reactions for the formation of sulfonic acids.…”

“…The direct sulfonation of Na 2 SO 3 (2 a) occurred with the best enantioselectivity and regioselectivity with the assistance of the catalyst made from Feringa's L1 ligand (entry 5). However, reactions catalyzed by the complex generated from L2-L4 occurred in moderate to good yields with a high level of enantio-and regioselectivities (entries [13][14][15]. Reactions conducted with the catalysts made from L5 and L6 took place with poor results (entries [16][17].…”

Catalytic Enantioselective Addition of Sodium Bisulfite to Chalcones

“…[6] Several multistep syntheses of chiral sulfonic acids have been reported. [7][8][9][10][11] However, the simple addition of bisulfite to olefins, discovered over a century ago, [12] remains the most straightforward access to aliphatic sulfonic acids. This reaction employs reactants in large excess and requires high temperature, which limits its synthetic utility.…”