The Synthesis of CP-263,114 and CP-225,917: Striking Long-Range Stereocontrol in the Fashioning of C7

Natural products with anti-Bredt and bridgehead double bonds

Well over a hundred years ago, Professor Julius Bredt embarked on a career pursuing and critiquing bridged bicyclic systems that contained ring strain induced by the presence of a bridgehead olefin. These endeavors founded what we now know as Bredt's rule (Bredtsche Regel). Physical, theoretical, and synthetic organic chemists have intensely studied this premise, pushing the boundaries of such systems to arrive at a better understood physical phenomenon. Mother nature has also seen fit to construct molecules containing bridgehead double bonds that encompass Bredt's rule. For the first time, this topic is reviewed in a natural product context.

Synthesis of a versatile metacyclophane macrolactam

As Hsp90 has emerged as a promising target for the development of cancer chemotherapeutics, so has the need for systematic evaluation of structure-activity relationships between natural product inhibitors and this molecular chaperone. Utilizing our chimera approach, which encompasses the quinone moiety of geldanamycin and the resorcinol moiety of radicicol, molecules have been produced that are highly effective inhibitors of the Hsp90 protein folding machinery. These chimeric inhibitors contain metacyclophane macrolactams that are difficult to cyclize and modify for incorporation of functional diversity. To circumvent this problem, a highly diversifiable alpha-bromo-alpha,beta-unsaturated ester has been prepared, which allows for the introduction of various functionalities that enable elucidation of structure-activity relationships between chimeric compounds and Hsp90. The rationale, synthesis, and optimization for such a molecule is reported herein.

Cascade Reactions in Total Synthesis

The design and implementation of cascade reactions is a challenging facet of organic chemistry, yet one that can impart striking novelty, elegance, and efficiency to synthetic strategies. The application of cascade reactions to natural products synthesis represents a particularly demanding task, but the results can be both stunning and instructive. This Review highlights selected examples of cascade reactions in total synthesis, with particular emphasis on recent applications therein. The examples discussed herein illustrate the power of these processes in the construction of complex molecules and underscore their future potential in chemical synthesis.

Palladium-catalyzed cross-coupling reactions in total synthesis

In studying the evolution of organic chemistry and grasping its essence, one comes quickly to the conclusion that no other type of reaction plays as large a role in shaping this domain of science than carbon-carbon bond-forming reactions. The Grignard, Diels-Alder, and Wittig reactions are but three prominent examples of such processes, and are among those which have undeniably exercised decisive roles in the last century in the emergence of chemical synthesis as we know it today. In the last quarter of the 20th century, a new family of carbon-carbon bond-forming reactions based on transition-metal catalysts evolved as powerful tools in synthesis. Among them, the palladium-catalyzed cross-coupling reactions are the most prominent. In this Review, highlights of a number of selected syntheses are discussed. The examples chosen demonstrate the enormous power of these processes in the art of total synthesis and underscore their future potential in chemical synthesis.