Transfer from Bitcoin Core to Electrum expired before full synchronization. Where are the bitcoins? I started using Bitcoin Core and transferred coins to this wallet. When synchronization got to the point where the coins showed up in the wallet I sent them on to an Electrum wallet, although Core had still not fully synchronized. 

The Electrum incoming transaction then expired before the Core wallet had fully synchronized. Now Bitcoin Core has finished synchronization and shows the outgoing transaction and empty balance although the Electrum wallet never received the transaction.

Are these bitcoins lost or is then anyway to reclaim them?

Thanks.
If you broadcasted the transaction, it will appear on the other end, eventually.

I suggest you to first go to https://blockchain.info/ and look-up your electrum address or the transaction ID. There, you should see if the transaction is still unconfirmed or has already been confirmed.
In both cases, you should see it in electrum. If you don't see it, try exiting electrum, deleting blockchain_headers file in %appdata%\Electrum, and running it again. This will force it to re-scan everything.