<i>Cinchona</i> Alkaloid Catalyzed Sulfa-Michael Addition Reactions Leading to Enantiopure β‑Functionalized Cysteines

Sulfa-Michael additions to α,β-unsaturated <i>N</i>-acylated oxazolidin-2-ones and related α,β-unsaturated α-amino acid derivatives have been enantioselectively catalyzed by <i>Cinchona</i> alkaloids functionalized with a hydrogen bond donating group at the C6′ position. The series of <i>Cinchona</i> alkaloids includes known C6′ (thio)­urea and sulfonamide derivatives and several novel species with a benzimidazole, squaramide or a benzamide group at the C6′ position. The sulfonamides were especially suited as bifunctional organocatalysts as they gave the products in very good diastereoselectivity and high enantioselectivity. In particular, the C6′ sulfonamides catalyzed the reaction with the α,β-unsaturated α-amino acid derivatives to afford the products in a diastereomeric ratio as good as 93:7, with the major isomer being formed in an ee of up to 99%. The products of the organocatalytic sulfa-Michael addition to α,β-unsaturated α-amino acid derivatives were subsequently converted in high yields to enantiopure β-functionalized cysteines suitable for native chemical ligation

Relational values of nature: leverage points for nature policy in Europe

Relational values reflect the qualities of the relationships between humans and nature, such as care, social bonding, place attachment and spiritual meanings. In this perspective article, we argue that understanding relational values is vital for nature conservation, and we identify how incorporation of these values may function as leverage points for achieving more effective nature policy. We discuss the distinctive features of the concept of relational values and elaborate how relational values strongly influence people’s perceptions of, engagement with and action for nature. Relational values can also provide important deep leverage points for policy interventions aiming to support citizen’s contribution to nature conservation, to strengthen biodiversity policy and the relationship between people and nature. Based on three realms of leverage (re-think, re-structure and re-connect), we distinguish six routes through which relational values can be integrated in policies and practices of nature conservation: (1) incorporation of pluralized meanings of nature; (2) the uptake of relational language in policy discourse; (3) a prioritization of landscape-based policy; (4) empowering citizens in nature conservation; (5) re-orienting nature education to stimulate people’s personal bond with nature; and (6) using digital technology to stimulate new relationships with nature