ASYMMETRIC DIELS-ALDER REACTIONS OF VINYLOGOUS URETHANES

乙烯基聚氨酯的不对称狄尔斯-阿尔德反应

• 批准号: 3308759
• 负责人: RICHARD H SCHLESSINGER
• 金额: $ 23.6万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-04-01 至 1996-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3308759
• 关键词: Diels Alder reaction; antineoplastic antibiotics; carbohydrate analog; diene; stereochemistry; urethan

The objective of this new proposal is to devise a number of total syntheses of complex carbocycles exploiting a novel methodology, that employs chiral dienes ultimately derived from tetronic acids and proline in Diels-Alder (D-A) type reactions. The D-A reaction has become an extension of vinylogous urethane lactone (VUL) enolate carbon-carbon bond formation reactions. As functionally opulent dienes, these systems offer several synthetic advantages relative to other cycloaddition reactions. A major benefit is the formation of a bicyclic ketal, which can function as a protecting group for subsequent synthetic manipulations. These incipient nonracemic cycloadducts permit facile control in the introduction of additional asymmetric centers to the rigid oxa-[2.2.1]- bicyclic heptyl system. The ease of synthesis and accessibility of inexpensive starting materials makes these dienes applicable to large scale asymmetric synthesis. We intend to demonstrate the versatility of these novel dienes within the context of several short enantioselective syntheses of biologically active compounds, while concomitantly studying the origins of their p facial selectivity and expanding their applicability. It is our intent to effect a brief and efficient construction of the antitumor and antimicrobial, esperamicin as the aglycone (24) and several biologically active and distinct pseudo-sugars (50, 34, 43) using this methodology.

这个新提案的目的是设计出一些总