Terrain synthesis

In an earlier ehapter in this series (Volume 1, Chapter 13) written twenty years go, one of us compared the exercise of a complex synthesis to a tortuous journey "that continually asserts the unpredictability of travel through all but the most familiar terrain." And that was a chapter describing a synthesis of the Prelog-Djerassi lactone Onward travel to methynolide, the simplest of all the macrolide aglycons, seemed like a daunting task for its time. It is a measure of the distance synthetic organic chemistry has come in the past two decades that we can now plan and execute routes to the most complex macrolide structures found in nature, albeit with a blueprint that usually requires many steps and at a level of overall efficiency that removes practical value from the sequence in most... 

---