From dipivaloylketene to tetraoxaadamantanes

• Gert Kollenz and
• Curt Wentrup

Beilstein J. Org. Chem. 2018, 14, 1–10, doi:10.3762/bjoc.14.1

• been discussed [11], but due to the lack of functional groups, tetraoxaadamantanes have remained largely laboratory curiosities. It is worth noting that the 2,4,10-trioxaadamantanes, which are orthoesters, are well known [12][13], and the natural product muamvatin [14] is a 2,6,9-trioxaadamantane

Approaches to α-amino acids via rearrangement to electron-deficient nitrogen: Beckmann and Hofmann rearrangements of appropriate carboxyl-protected substrates

• Sosale Chandrasekhar and
• V. Mohana Rao

Beilstein J. Org. Chem. 2012, 8, 1393–1399, doi:10.3762/bjoc.8.161

• ), their carboxyl groups being masked as a 2,4,10-trioxaadamantane unit (an orthoacetate). The oxime mesylates have been rearranged with basic Al2O3 in refluxing CHCl3, and the malonamic acids with phenyliodoso acetate and KOH/MeOH. Both routes are characterized by excellent overall yields. Structure

• rearrangement; orthoacetate; trioxaadamantane; Introduction The synthesis of α-amino acids remains of continuing interest for at least two reasons: Firstly, obtaining a particular amino acid via protein hydrolysis implies its separation from other amino acids (and their possible wastage, particularly on large

• two approaches to amino acids in which the key step is either the Beckmann or the Hofmann rearrangement, as described in the following. Results and Discussion Beckmann rearrangement approach The key substrate is the known 3-phenacyl-2,4,10-trioxaadamantane (1, Scheme 1) [14][15][16]. (An improved