Oxa Bowls: Synthesis and $C-H^{...}O$ Mediated Solid State Structure of Pentaoxa-[5]-peristylane

Mehta, Goverdhan and Vidya, Ramdas (2001) Oxa Bowls: Synthesis and $C-H^{...}O$ Mediated Solid State Structure of Pentaoxa-[5]-peristylane. In: Journal of Organic Chemistry, 66 (21). pp. 6905-6912.

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Abstract

We have conceptualized [n]-oxa-[n]-peristylanes as a new family of oxa bowls having a crownlike shape and potential $C_n_v$ symmetry. Recognizing their equivalence to the corresponding [n]-formyl-[n]-cycloalkanes, we have conceived of a general synthetic strategy in which intramolecular cascade acetalizations constitute the pivotal step. As our first synthetic effort, we describe the synthesis of pentaoxa-[5]-peristylane 3b from the readily available Diels-Alder adduct 10 of 5,5- dimethoxytetrachlorocyclopentadiene and maleic anhydride. The norbornyl framework of 10 serves as the rigid structural matrix to build the stereochemical features and latent aldehyde functionalities as in 9 through a series of functional group adjustments. Ozonation of 9 furnished 3b in a one-step transformation in which five tetrahydrofuran rings were generated. While 3b exhibited $C_5_v$ symmetry in solution, its symmetry in the solid state was observed to be $C_s$ by X-ray crystallography. In the solid state, 3b is endowed with a multicolumnar architecture, whose distinctive features include C-H...O interactions involving the less acidic cyclopentane hydrogens. Indeed, all the 10CH moieties and 5 oxygen atoms (through both the lone pairs) of 3b $(C_1_0H_1_0O_5)$ are involved in short C-H...O contacts (strong and soft) and its crystal structure indicates marked proclivity toward maximal hydrogen bonding.

Item Type:	Journal Article
Publication:	Journal of Organic Chemistry
Publisher:	American Chemical Society
Additional Information:	Copyright for this article belongs to American Chemical Society.
Keywords:	Oxa Bowls;Synthesis;C-H...O;Mediated;Solid State Structure;Pentaoxa;peristylane.
Department/Centre:	Division of Chemical Sciences > Organic Chemistry
Date Deposited:	25 Aug 2008
Last Modified:	19 Sep 2010 04:17
URI:	http://eprints.iisc.ac.in/id/eprint/2678

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