Diastereoselective Diels−Alder Reactions of a Novel Cyclopropenyl-Containing Chiral Auxiliary

Abstract

A novel cyclopropenyl-containing 1,3-spiroaminoalcohol auxiliary has been used in a variety of asymmetric Diels-Alder reactions providing endo adducts with diastereomeric ratios ranging from 2:1 up to >99:1. In addition, unexpected regiochemistry was observed for a Diels-Alder reaction between cyclopropenyl dienophile and 4-vinyl-1,2-dihydronapthalene.

Catalytic Asymmetric exo-Selective 1,3-Dipolar Cycloaddition of Azomethine Ylides and Ethyl Cyclopropylidene Acetate for Construction of 5-aza-Spiro[2,4]heptane Motif

“…Brandi 小组 [6] 于 2006 年实现了 手性辅基诱导的硝酮与环丙基亚甲基乙酸乙酯参与的 1,3-偶极环加成反应. Keay 小组 [7] 和 Kuethe 小组 [8] [9] , 其中作为亲 1,3-偶极子的环丙基亚甲基 乙酸酯中的环丙烷单元得到保持并形成相应的螺环结 构(图 2a). 众所周知, 手性分子的生物活性与其立体构 型密切相关, 生物体对手性药物分子有着独特的识别作 用, 手性分子的构型不同, 其药理活性可能不相同 [10] .…”

Total Syntheses of the Tetracyclic Cyclopiane Diterpenes Conidiogenone, Conidiogenol, and Conidiogenone B

“…Our synthesis commenced with the preparation of the rearrangement precursor 7 from 10 and 11 . Treatment of the freshly prepared Grignard reagent 11 with ester 10 in the presence of CuCl and TMSCl, followed by the addition of LiOH, afforded acid 12 in 60 % yield (Scheme ).…”

Recent developments in the reactivity of methylene- and alkylidenecyclopropane derivatives

“…110 The corresponding endo-cycloadducts were obtained in moderate-to-high yields (20e88%) with diastereomeric ratios ranging from 2:1 to 99:1. Some of the best results are collected in Scheme 70.…”