Quniazolines. Part XIII. Synthesis and stereochemistry of trans- and cis-decahydroquinazolines

Abstract

trans-Decahydroquinazoline was obtained by stereoselective reduction of 5,6,7,8-tetrahydroquinazoline with sodium and ethanol. The stereoselectivity was confirmed by authentic syntheses of trans- and cis-decahydroquinazolines. The preferred conformations of these and their intermediates were deduced from their ¹H n.m.r. spectra. The absolute configuration of (–)-trans-decahydroquinazoline was shown to be 4aR, 8aS