A PRACTICAL ASYMMETRIC-SYNTHESIS OF A 1,7-ENYNE A-RING SYNTHON EN-ROUTE TOWARD THE TOTAL SYNTHESIS OF VITAMIN-D-3 ANALOGS

[摘要] A concise synthesis of a key A-ring synthon of 1 alpha,25-dihydroxyvitamin D-3, 1, has been achieved in 8 steps starting from readily available, inexpensive ethyl-4-chloroacetoacetate. This synthon serves as one of two main coupling partners in our previously developed Pd-catalyzed alkylative enyne cyclization leading toward the total synthesis of 1 alpha,25-dihydroxyvitamin D-3 and potentially useful analogues.

[发布日期] 1994-10-31