High stereochemical diversity and applications for the synthesis of marinenatural products: A library of carbohydrate mimics and polyketide segments

We have developed a powerful concept for the rapid assembly of a series of twenty-four homochiral building blocks from simple racemic trans-2,4-dimeth yl-8-oxabicyclo[3.2.1]oct-6-en-3-one. The series comprises eight stereochem ical pentades of anomeric [3.3.1]lactone acetals, eight stereochemical tetr ades of anomeric carbohydrate mimics, and eight stereotetrades of acyclic p olypropionate units. The utility of these enantiopure materials (average 94 % ee) in natural product synthesis is demonstrated and shown to complement the popular aldol method.