高鏡像選擇性銠(I)/掌性雙烯配體催化芳香基硼酸對反丁烯二酸酯進行不對稱1,4加成反應及其合成應用 -α2腎上腺素受體拮抗劑全合成 -氮-苄基-3-苯基吡咯啶的不對稱合成

Abstract

利用天然物左旋醋酸冰片酯49合成高穩定性的掌性雙環[2.2.1]雙烯配體，並結合銠（I）催化芳香基硼酸對反丁烯二酸酯進行不對稱1,4-加成反應。在這個催化系統中，銠(I) (1mol% of Rh)催化量和掌性雙烯配體進行不對稱1,4-加成反應，產物具有高產率和高立體選擇性（高達>99.5％ ee值）。並將其應用在合成掌性3-(2-甲氧基)苯基吡咯啶（α2 -腎上腺素受體拮抗劑）和合成掌性氮-苄基-3-苯基吡咯啶。

A new set of stable chiral bicyclo[2.2.1] diene ligands were prepared from (-)-bornyl acetate 49, and were employed in the rhodium(I)-catalyzed asymmetric 1,4-addition of arylboronic acids to fumarates. In this catalytic system, rhodium-diene complex (1.0 mol%) generated in situ from chiral diene 53a and [RhCl(C2H4)2]2 successfully yielded the corresponding adducts with good to excellent chemical yields and excellent levels of enantioselectivities (up to >99.5% ee). This methodology was demonstrated by its utilization in the enantioselective total synthesis of 3-(2-methoxyphenyl)pyrrolidine (an α2-adrenoceptor antagonist) and asymmetric synthesis of N-benzyl-3-phenylpyrrolidine.