Asymmetric syn‐Dihydroxylation of β‐Substituted (2R)‐N‐(α,β‐Enoyl)bornane‐10,2‐sultams

Abstract

Variously β‐substituted (2R)‐N‐[(E)‐α,β‐enoyl]bornane‐10,2‐sultams were oxidized with OsO4/4‐methylmorpholine 4‐oxide in a highly stereoselective manner. In all cases, the attack occurred on the C(α)‐re face. The absolute configurations of all products were determined by chemical correlation. Mechanistic considerations about the reactive conformation as well as fully refined X‐ray crystal structures of the dihydroxylated products are discussed. New neutral conditions for sultam acylation, applicable to the preparation of the taxol and Taxotere® C(13) side chain as well as of Cardizem® and chloramphenicol precursors, are also presented.

Diastereoselective 1,3‐Dipolar Cycloadditions of Chiral Derivatives of 2‐Oxoethanenitrile Oxide to Noncyclic Conjugated Symmetrical Alkenes

“…See [39]. All measurements of crystals were performed on a KM4CCD k-axis diffractometer with graphitemonochromated MoK a radiation ( Table 5).…”

Recent advances in the application of the Oppolzer camphorsultam as a chiral auxiliary

“…44 The C2 symmetrical fumaramide 58 with two Oppolzer camphorsultam moieties has previously been employed in reactions such as cycloaddition and dihydroxylation reactions. 45,46 As shown in Scheme 14, the fumaramide 58 was reacted with a number of Grignard reagents, obtained from the corresponding alkyl bromides and chlorides, to yield a mixture of diastereomers 59 and 60 (Table 4).…”

Grignard 1,4‐Additions to para‐Substituted (2R)‐N‐Cinnamoylbornane‐10,2‐sultam Derivatives: Revised Configuration for the N,OAc‐Keteneacetal Formation in the Presence of Cu(I)

“…Crystallographic data of 3a were deposited as supplementary material with the Cambridge Crystallographic Data Centre and allocated the deposition number CCDC‐1428062. These data can be obtained free of charge via http://www.ccdc.ac.uk/data_request/cif (see ).…”