Lysine is incorporated specifically, and via a symmetrical intermediate, into ring A of vertine (3) and lythrine (6); the cis-and trans-quinolizidinones, (9) and (lo), are, respectively and specifically, effective precursors for (3) and (6), and the corresponding mono-0-methyl ethers (11)-( 14) are not u t i I ized for a I ka lo id biosy n t hesis.

Lysine is incorporated specifically, and via a symmetrical intermediate, into ring A of vertine [11] and lythrine [10]; the cis-and irawr-quinolizidinones, 25 and 19, are, respectively and specifically, effective precursors for 11 and 10, and the corresponding mono-O-methyl ethers 15,17,21, and 23 are not effectively utilized for alkaloid biosynthesis.