Phosphite-mediated conversion of benzaldehydes into stilbenes via umpolung through a dioxaphospholane intermediate

AbstractThe phosphite-mediated coupling of two benzaldehydes into 2,2,2-triethoxy-1,3,2-dioxaphospholanes was investigated using 13C NMR spectroscopy and was found to be very sensitive to the nature of the ortho/para substituents, and promoted by electron-withdrawing groups (EWGs). Stilbene-extended tetrathiafulvalenes were prepared by heating the intermediate dioxaphospholane, containing aldehyde substituents at para positions and ethynyl groups at ortho/meta positions, with 1,3-dithiol-2-thiones in P(OEt)3. While EWGs promoted dioxaphospholane formation, electron-donating groups (EDGs), generated by conversion of the aldehydes into dithiafulvenes, promoted subsequent conversion into an alkene

Gudmund Hat

GUDMUND HATTLike a fresh squall - squall indeed, for breeze is too light a word - Hatt came storming in the Twenties in over archeological field-work in Denmark, at least the field-work which covered settlements house-sites and fields, especially of the lron Age. True that the National Museum had experience in these matters, but its people were at that time to a degree inhibited by the old and somewhat tyrannical excavation technique worked out in the Nineties, which could allow the archeologist to return home from his site with service fully paid to the square-meter-system rather than to the realities of life which it covered. When Hatt came to the National Museum he was already, in other fields than the archeological, a tried and mature research-worker. He broke through. He was not one who would stand still before an established technique. A score of years ago I had occasion to write the following, from personal experience, about Hatt's contribution:"It can scarcely be doubted that several of the earlier investigations of settlements, which describe culture levels, stone-settings, and the like, in fact dealt with remains of houses, the type and extent of which were not recognised. That stone-settings on lron-Age settlements as a rule do not comprise the actual house-sites but on the contrary the area immediately surrounding them (the cobbled yards, roads and paths) is a view which we owe to Hatt's researches, just as it is he who has taught Danish archeologists the difficult art of recognising the traces of prehistoric houses which have not been destroyed by fire."Hatt united a clear and powerful breadth of view with a close attention to detail. With massive energy, untiringly and with harsh demands upon himself and others, Hatt threw himself into his work - with results that measured up to the effort. Look only at his literary production! The whole way of life and work, the basic premises of existence of the Iron-Age farmer is here illuminated by a wealth of facts. Long will researchers dip into the overflowing cauldrons of Hatt's treatises. His two main subjects are, of course, prehistoric houses and prehistoric fields. From site to site he moved his tent over north and west Jutland, quartering his ground like a burly buzzing bumble-bee. Skørbæk Solbjerg Fredsø Ginderup Rødklit Nørre-Fjand Oksbøl - a handful only among a riot of flowers. And for the recognition, demonstration and preservation of our prehistoric fields of Jutland Hatt was pioneer and prophet.It must give him satisfaction that the next generation of Danish archeologists can do other and more than passively accept and exploit his achievements. That they also can pioneer!Johannes Brøndste

Erik Westerby

Mindeord for Erik Westerb

Forord

PrefaceThis photograph shows Dr. Therkel Mathiassen as we Danish archeologists best know him: out in the field, observant, critical, deeply interested, with wrinkles innumerable telling their tale of good humour and intelligence. Mathiassen the omnipresent, the untiring toiler, never sparing himself but always expecting a little more of himself than of others, the quiet, balanced, unhurried worker who nevertheless works at such a phenomenal speed; this is the Mathiassen we know, as we are accustomed to seeing him. What archeological research and the preservation of ancient monuments in Denmark in actual fact owe to him we shall not forget. Let me stress the following two points:In the sphere of research into Denmark's Stone Age Therkel Mathiassen will long be remembered as the great collector and systematizer of new and primary material. Our knowledge of the millenia of Denmark's Mesolithic Period is based to a considerable extent upon the numerous settlement sites and "stations" discovered by Mathiassen in the field and published by him in the literature of the subject. Think only of his work in Aamose or with the Gudenaa siles - not to mention his contributions in the sphere of the New Stone Age or of systematic research into the history of ancient settlement.The other main point is that of preservation of ancient monuments. Since the law protecting these monuments was passed in 1937 no one has laboured remotely comparably with Mathiassen to explain, practise and adapt the provisions of the statute, and in no less degree to fight for actual literal preservation, lest posterity should see the preservation statutes confined to the obscurity of paper, an imaginary life ignored in practice. This battle is still going on, and if a solution is ever found to the problem of an effective watch and ward over Denmark's ancient monuments a large share of the praise for this will be owed to Mathiassen.In the field of Eskimo research Dr. Mathiassen is, as is well known, a figure of international repute, by reason of the work of his youth and early manhood. But the past twenty years of his everactive life he has devoted to a preponderant degree to the excavation of his native soil and to the shrewd and accurate assessment of its fruits. In his department of the National Museum, the former "Oldnordisk Museum", Dr. Mathiassen is a highly respected and beloved chief. Nor could one expect it to be otherwise.Gentle reader, let these lines and the photograph which accompanies them illuminate for you the background and the reason why.Johannes Brøndste