Intra- and intermolecular reaction selectivities of γ-substituted adamantanylidenes.

A study of adamantanylidenes having a γ-substituent (R) was undertaken to gauge how inductive and steric effects of remotely positioned functional groups influence intra- and intermolecular product selectivity. 3H-Diazirines were thermolyzed or photolyzed to generate the corresponding carbenes. On rapid heating, the resulting carbenes isomerized to 2,4-didehydroadamantanes by intramolecular 1,3-CH insertions.

Structure-reactivity relationships: reactions of a 5-substituted aziadamantane in a resorcin[4]arene-based cavitand.

The complexation properties of two novel C5-substituted adamantanediazirines within the resorcin[4]arene-based cavitand 4 were investigated in DMSO-d(6), revealing that binding is up to 1.4 kcal/mol stronger for halogenated adamantanediazirines when compared with the unsubstituted species. The thermal behavior of 5-bromo-2-aziadamantane (3) was investigated by DSC analysis as the first representative of the adamantanediazirine family in the neat solid state, as well as encapsulated within the aromatic cavity of cavitand 4.

Reversal of diastereoselectivities in intra- and intermolecular reactions of 2-adamantanylidenes primarily caused by electron-donating and electron- withdrawing substituents on C5.

[reaction: see text] A reversal of diastereoselectivity was observed for novel 5-(trimethylsilyl)adamantan-2-ylidene (1c) with regard to 5-hydroxyadamantan-2-ylidene (1a). Ostensibly in intermolecular reactions, 5-substituted 2-adamantanylidenes (1) are sterically unbiased. However, inductive effects originating from the pendant group bend the divalent carbon bridge of 1 either toward (ERG's, e.

2,6-Diaziadamantane: a single-crystal X-ray diffraction study and theoretical calculations.

The first single-crystal X-ray diffraction study of 2,6-diaziadamantane (2), a compound containing two diazirine functionalities, and B3LYP/6-311+G* and MP2/6-311+G* calculations relating to the interaction between carbon-nitrogen and nitrogen-nitrogen covalent bonds and electron density within the diazirine rings have been performed. In addition, the protonation of 2-aziadamantane (1) has been investigated. The single-crystal X-ray diffraction study of 2, including UV/vis titrations of 1, corroborate the theoretical conclusion that the low basicity can be attributed to a rehybridization of the nitrogen lone pairs.