dictyostatin and its analogs show great promise as new anticancer agents . the present invention provides dictyostatin analogs , synthetic intermediates for the synthesis of dictyostatin analogs , and synthetic methods for the synthesis of such analogs and intermediates . dictyostatin analogs can have the following structure or its enantiomer wherein r 1 is h , an alkyl group , an aryl group , an alkenyl group , an alkynyl group , or a halogen atom ; r 2 is h , a protecting group , an alkyl group , a benzyl group , a trityl group , — sir a r b r c , ch 2 or d , or cor e ; r a , r b and r c are independently an alkyl group or an aryl group ; r d is an alkyl group , an aryl group , an alkoxylalkyl group , — r i sir a r b r c or a benzyl group , wherein r i is an alkylene group ; r e is an alkyl group , an allyl group , a benzyl group , an aryl group , an alkoxy group , or — nr g r h , wherein r g and r h are independently h , an alkyl group or an aryl group ; r 3 is n where n is and integer in the range of 0 to 5 , — ch 2 ch —, — ch ═ ch —, — ch ═ c —, or — c ≡ c —; r 4 is wherein r 23a is h , a protecting group , an alkyl group , a benzyl group , a trityl group , — sir a r b r c , ch 2 or d , or cor e ; r 23b is h , a protecting group , an alkyl group , a benzyl group , a trityl group , — sir a r b r c , ch 2 or d , or cor e , or r 23a and r 23b together form a portion of six - membered acetal ring incorporating cr t r u ; r t and r u are independently h , an alkyl group , an aryl group or an alkoxyaryl group ; and r 5 is h or or 2b , wherein r 2b is h , a protecting group , an alkyl group , an aryl group , a benzyl group , a trityl group , — sir a r b r c , ch 2 or d , or cor e ; provided that the compound is not dictyostatin 1 .