Synthesis of functionalized arenes based on [3+3] cyclizations of 1,3-bis(silyloxy)-1,3-butadienes and related transformations and isolation of new chemical constituents of Symplocos racemosa [Elektronische Ressource] / vorgelegt von Muhammad Abid Rashid

Synthesis of Functionalized Arenes based on [3+3] Cyclizations of 1,3-Bis(silyloxy)-1,3-butadienes and related Transformations and Isolation of New Chemical Constituents of Symplocos racemosa I n a u g u r a l d i s s e r t a t i o n zur Erlangung des akademischen Grades doctor rerum naturalium (Dr. rer. nat.) an der Mathematisch-Naturwissenschaftlichen Fakultät der Universität Rostock vorgelegt von Muhammad Abid Rashid geboren am 13-04-1976 in Sahiwal, Pakistan Rostock 1-02-08 urn:nbn:de:gbv:28-diss2008-0018-2 i Dekan : 1. Gutachter : 2. Gutachter : Tag der Promotion : ii Affectionately Dedicated to Ammar, Umar, Usman, Umair and Ayesha “My beloved nephews and niece” iiiCONTENT Acknowledgements Abbreviations Sumary 1 Part A Synthesis of Functionalized Arenes based on [3+3] Cyclizations of 1,3-Bis(silyloxy)-1,3-butadienes and related Transformations Introduction 4 1. Regioselective Synthesis of ω-Bromo-3-ketosulfones, ω-Bromo-3-ktonitriles and 2-( ω-Bromoalkyl)benzofurans based on ′Ring-Closing / Ring-Opening ′ Strategy 7 1.1 Introduction 7 1.2 Results and Discussion 8 1.2.1. General mechanism for the cyclization of 1-bromo-2-chloroethane with 3-keto- sulfone dianion 8 1.2.1.