The Synthesis of Condensed Ring Compounds. XVI.¹ The Addition of Quinones to a Dienyne²

Abstract

Improved procedures are given for the preparation of a-and ß-D-xylopyranose tetrabenzoates, 2,3,4-tribenzoyl--D-xylopyranosyl bromide and 2,3,4-tribenzoyl-2-hydroxy-D-xylal.The latter compound was found resistant to hydrogenation under the conditions employed for the reduction of its acetyl analog. Revised physical constants for some of the substances are recorded.

The Dehydro-Diels−Alder Reaction

“…Some years later Butz and co-workers reported on the reaction of various dienynes 65 with electron-poor alkenes (maleic anhydride, fumarates, p -benzoquinone). The primarily formed cycloallenes 66 undergo a second Diels−Alder reaction providing compounds 67 as final products .…”

Double Dehydro‐Diels–Alder Reactions of 1,5‐Dien‐3‐ynes

“…This transformation was first reported in 1933 by Blomquist and Marvel 3a. A series of reports by Butz and co‐workers followed, in which the scope of the reaction was examined 3b–h. Consistently low yields (2–19 %) were reported for this rare4 transformation.…”

The Diels–Alder Reaction in Steroid Synthesis

“…were made in the 1940s and 1950s, [160][161][162][163][164] and an isolated report appeared in 1996. 165 The most recent investigation of this transformation was published by Paddon-Row and Sherburn in 2009.…”